DEV Community: Sofia Tarhonska

5 Best Email API for Laravel Developers Tested & Compared

Sofia Tarhonska — Thu, 26 Feb 2026 10:46:07 +0000

The best email APIs for Laravel developers are Mailtrap, SendGrid, Mailgun, Amazon SES, and Postmark.

To provide you with a fair and unbiased comparison of these APIs, I researched and tested them all with the help of Mailtrap email deliverability experts, security team, and developers.

Together, we integrated each API into a demo Laravel application, tested the most common use cases, sent a bunch of emails, tried out the key features, etc. This provided us with a clearer picture of the differences in deliverability rates, infrastructure quality, and other comparison criteria you should evaluate when choosing a Laravel email API.

Best email SDKs for Laravel: a snapshot

Mailtrap is the best email API for Laravel developers and product teams who need high inboxing rates, fast delivery, a developer-friendly experience, and reliability.
SendGrid is for large developer teams and enterprises that need a flexible API, a high level of multitenancy support, and extra quality-of-life features.
Mailgun is for teams who want to send mass emails while also being able to automatically validate their recipients’ addresses.
Amazon SES is for developer teams who are experienced working with the AWS infrastructure and could use its numerous integrations.
Postmark is for developers who want to send transactional emails with a highly configurable API while also having inbound email capabilities.

And here’s the most essential info you need to get started with the best email APIs for Laravel developers:

Laravel email API comparison: comparison criteria

We organized our comparison criteria into these categories:

Laravel integration
Developer experience
Webhooks
Email infrastructure
Email API flexibility
Pricing comparison
Customer support

Laravel integration

For starters, I present to you the essential information any developer would want to know before integrating an email API with their Laravel project.

Developer experience

Setup time & learning curve

You can integrate easily all of the Laravel email API providers that I listed in this article, although there are a few nuanced differences. More specifically:

Mailtrap provides an official Laravel bridge, which uses its very own, regularly updated and maintained, PHP SDK.
SendGrid can be integrated via a community-maintained s-ichikawa package, which provides a native Laravel mail driver.
Mailgun, Amazon SES, and Postmark integrate via the Symfony transport package. This is because Laravel 9+ uses Symfony Mailer as its underlying mail engine.

And here’s what you can expect when it comes to setup time and complexity:

MCP server support

MCP (Model Context Protocol) servers are essentially a quality-of-life feature that allows you to interact with email APIs while developing your project. For instance, you can manage email templates through your IDE without having to alt-tab from your workflow.

So, here’s a table that summarizes the capabilities of each email API provider in this article:

Webhooks

Webhooks are a staple tool for any developer serious about their project, especially those using an email API. Think of them as an extension that lets you get real-time notifications on key events like delivered or bounces, monitor engagement, etc.

All five email API providers on this list offer webhooks, although they are slightly different in the events they offer and retry logic:

Want the full comparison?

If you’d like to explore the complete breakdown, including detailed comparisons of email infrastructure, email API flexibility, pricing and customer support, check out the full version of our comparison of the best transactional email API for Laravel on Mailtrap's blog!

5 Best Email API for PHP Developers Tested & Compared: Here’s What I Found

Sofia Tarhonska — Wed, 25 Feb 2026 16:50:03 +0000

The best email APIs for PHP developers are Mailtrap, SendGrid, Mailgun, Amazon SES, and Postmark.

I researched and tested each of these services with the help of Mailtrap’s deliverability experts and security team. My goal was to identify the best email APIs for PHP developers by looking at real-world infrastructure needs rather than just reading marketing copy.

We created a demo application, integrated each API, and tested the most common use cases, such as sending transactional and marketing emails, trying out webhooks, etc. The differences between deliverability, setup speeds, and other comparison criteria were more than clear, to say the least.

Best email API for PHP: a snapshot

Mailtrap is the best PHP email API for developers and product teams who need high deliverability rates, a developer-friendly experience, and reliability.
SendGrid is for enterprises that need to send transactional and marketing emails at the same time from a single ecosystem.
Mailgun is for teams who want to send mass emails while also being able to automatically validate their recipients’ addresses.
Amazon SES is for experienced developer teams who are working with the AWS infrastructure and have spare time to set it up.
Postmark is for businesses that want to focus on sending transactional emails from a highly configurable API with a clean interface.

For your skimming convenience, I’ve compiled a little table that compares the essential info for the best PHP email APIs out there:

PHP email API comparison: comparison criteria

For easier navigation, we broke down our comparison criteria into the following categories:

SDK quality
Frameworks compatibility
Developer experience
Webhooks
Email infrastructure
Pricing comparison
Customer support

SDK quality

When it comes to SDK quality, I noted down the most important information any developer could use before adopting it, such as unpacked size and minimum PHP version.

Frameworks compatibility

Since we’ve included only the best APIs on this list, you can rest assured that they all offer well-maintained SDKs for major frameworks, such as Laravel and Symfony.
This makes it straightforward to plug into most modern apps, as you can keep your existing mailers and simply swap the transport layers when integrating a PHP-based email API into your stack.

Developer experience

Setup time & learning curve

All five providers offer Composer-installable SDKs, clear quickstarts, and sample code, so a basic integration can usually be completed in under an hour once your account and domain are verified.

However, there are a few nuances, namely:

Mailtrap provides very simple PHP integration with ready-made code samples and environment-based configuration, making it easy to drop into existing apps for email sending.
SendGrid and Mailgun both rely on official PHP SDKs installed via Composer and require API key management plus some familiarity with their message models, but their quickstart guides and examples keep initial setup relatively straightforward.
Amazon SES adds extra steps around AWS SDK configuration, IAM permissions, and understanding SES-specific sending limits and regions, so PHP developers who are new to AWS may spend more time on initial setup and troubleshooting.
Postmark’s official PHP client is distributed via Composer and comes with simple helper methods for sending transactional messages and handling templates, which keeps the integration surface small and easy to reason about for most PHP projects.

Note: The differences in setup time and learning curve surface when you start using platform-specific features like AWS IAM for SES, or simply advanced features like templates and webhooks.

Here’s what you can expect from the setup time and complexity of each provider, after you’ve been verified as a sender:

Wrapping up

We hope you enjoyed this summary of transactional email APIs for PHP. If you want to explore the full version of it, including our deep-dive into webhooks and pricing, you can visit Mailtrap's blog page!

5 Best Email API for Python Developers Tested & Compared

Sofia Tarhonska — Wed, 04 Feb 2026 15:07:47 +0000

The best email APIs for Python developers are Mailtrap, Mailgun, SendGrid, Amazon SES, and Postmark.
Let's dive into details!

SDK quality & framework compatibility

All five providers offer Python SDKs and they’re compatible with popular frameworks. I tested each with Django, Flask, and FastAPI to assess real-world integration. Even so, note that the given packages have their quirks, some requiring manual intervention and additional configurations to work as intended.

Developer experience

Setup time & learning curve

Generally, all providers offer a relatively fast setup and quickstart instructions after you get verified as a sender. I haven’t accounted for the domain and sender verification since it partially depends on the domain you’re using. And there are provider specific procedures, for instance, AWS SES keeps you in a Sandbox for one or two work days.

Mailtrap: ~5 minutes - Clear documentation and intuitive API key setup make the process pretty easy.
Postmark: ~5 minutes - Similar to Mailtrap, Postmark requires minimal configuration and clean documentation helps speed up the process.
Mailgun: 10-15 minutes - Navigating the docs to get the SDK up and running can get tricky, especially if you want to add the email verification.
SendGrid: 10-15 minutes - There are additional configurations for API key management, and you can also structure payloads in different ways.
Amazon SES: 15-20 minutes - the steepest learning curve mostly due to AWS specifics, including the IAM setup. The given estimate is for someone already familiar with Amazon setup, not a novice.

Documentation quality

Overall, I can’t say that any of the providers have poor documentation, otherwise they wouldn’t be in the list. However, the clarity and depth of the docs make all the difference.

For instance, Mailtrap and Postmark are the clearest and easiest to navigate. SendGrid is the most comprehensive by far, but it’s at the expense of navigation (maybe even clarity) since they have a bunch of legacy docs.

Webhooks

Webhooks let your application react to email events in real-time. Here's what each provider supports:

Mailtrap: Best Python email API

G2: 4.8/5 Capterra: 4.8/5

Mailtrap works best for Python development teams building applications that require high inboxing rates and industry-best analytics.

The platform offers both SMTP and API-based sending with no rate limits and customizable throttling. Key capabilities include 500 messages per batch call, up to 10MB payload support, and 40 webhook retries every 5 minutes with event batching up to 500 events per call.

Security & compliance

Mailtrap is ISO 27001:2022 certified (since April 2024) and GDPR compliant. The platform is actively pursuing SOC 2 certification. All data is encrypted in transit via TLS, with SSO and 2FA support.

Mailgun: Best for validation

G2: 4.2/5 Capterra: 4.3/5

Mailgun is built for developers who need to send at scale and want granular control over routing, validation, and delivery optimization. The comprehensive email validation tools help maintain clean recipient lists and protect sender reputation.

The service provides both REST API and SMTP access, plus inbound email parsing. Features include message IDs for debugging and comprehensive webhook support for delivered, opened, clicked, bounced, complained, and unsubscribed events.

Security & compliance

Mailgun holds SOC 2 Type II certification, ISO 27001, and is HIPAA eligible (BAA available). GDPR compliant with DPA available.

Wrapping up

We hope you have found this article to be useful and interesting, and in case you want to read the full version and see who other 3 best email API for Python developers are, check the Mailtrap's blog!

5 Best Email API for Node.js Developers Tested & Compared

Sofia Tarhonska — Wed, 21 Jan 2026 20:15:03 +0000

The best email APIs for Node.js developers are Mailtrap, Mailgun, SendGrid, Amazon SES, and Postmark.

I tested each by building a demo application and integrating all services to find which provides the best SDK.

Read on for complete results.

Node.js email API comparison

SDK quality

SDK ‘quality’ comes down to three things: ease of integration (how fast can you get started), maintainability (is it actively updated and supported), and developer experience (clear docs, good error messages, TypeScript support).

Frameworks compatibility

All five providers work seamlessly with major Node.js frameworks including Express.js, Next.js, Koa, Fastify, NestJS, and Hapi. The SDKs are framework-agnostic, meaning integration follows standard patterns regardless of your tech stack.

AWS SES offers additional native support for AWS Lambda and Vercel serverless functions, making it particularly well-suited for AWS-native architectures.

For most teams, framework compatibility won't be a deciding factor, as all providers support modern async/await patterns and integrate cleanly into any Node.js application.

Documentation

All the providers offer good documentation that can get you started with relative ease. However, the devil is in the details. So, here are some pointers to help you understand the nuances.

Mailtrap documentation is the most balanced. It has clean practical docs and examples that are immediately applicable. Also, major plus are video guides and deliverability tips.

Mailgun documentation is balanced as well. You get good examples with a decent amount of detail. Nonetheless, I found the navigation challenging.

SendGrid documentation is comprehensive, but it’s a blessing and a curse. There’s a lot of legacy content for different API versions which makes the whole experience confusing.

Amazon SES documentation is super comprehensive. But, as with any AWS docs, it’s very complex if you don’t have the experience, and you’d be hard pressed to find SDK examples.

Postmark documentation is similar to Mailtrap. The docs are balanced, clear, and practical. Though, if you’re looking for some advanced applications and tips, it’s best to check community forums.

MCP server support

MCP (Model Context Protocol) enables AI assistants to interact directly with email APIs for automated sending and management. Again, all providers have MCP servers, but the approach and the type of API calls differ, so here’s a quick breakdown:

Mailtrap has an official MCP and focuses on deliverability with email, template, and sandbox management. And it supports sending to multiple recipients.

Mailgun has an open-source MCP and you can send emails and retrieving analytics. Note that there are spinoffs, so make sure to use the official version.

SendGrid also has community-created MCP servers with capabilities that include campaigns, contacts, and status. However, the API surface is complex and may require manual tuning of the setup.

Amazon SES has a sample SESv2 MCP server for AI-assisted sending. It demands intensive setup and, in my experience, it’s not the SDK-like simplicity one could expect.

Postmark offers an official MCP server with email and template management as well as stats and tracking.

Mailtrap: Best Node.js email API

Mailtrap provides the best email API service for Node.js developer and product teams. It is a modern email platform with focus on high inboxing rates, fast delivery, and industry-best analytics.

Companies like PayPal, Atlassian, Adobe, Calendly use Mailtrap for their email infrastructure.

Why is Mailtrap the best for Node.js developers

Official TypeScript SDK: Built with TypeScript for type safety and better developer experience with auto-completion and compile-time error checking.
Start sending in minutes: Clean API design with intuitive REST principles — go from npm install to your first sent email in under 5 minutes.
Email API flexibility: No rate limits with customizable throttling, 500 messages per batch call, and up to 10MB payload support for attachments, full API control over templates, suppression lists, email categories, and per-domain token management with granular permissions.
Advanced webhooks: 40 retries every 5 minutes with automatic failure detection, event batching up to 500 events per call to reduce server load, and email notifications when webhooks fail.
High deliverability by design: 78.8% inbox placement rate across Gmail, Outlook, and Yahoo.
Separate email streams: Email endpoints for transactional and bulk messages protects your critical notifications from marketing campaign reputation issues.
Actionable analytics: Track opens, clicks, bounces, and delivery with detailed logs up to 30 days.

Mailgun: Best for email validation

As mentioned earlier, Mailgun is best for developers who need email validation. It provides API-first integration with focus on batch sending, scalability, and list quality.

Email deliverability test results: Mailgun achieved 71.4% of emails landing in the primary inbox.

Why Node.js developers choose Mailgun

TypeScript support: Complete type definitions available through separate package with full IDE auto-completion and compile-time error checking.
Email validation API: Pre-send validation against 450+ billion email database checks DNS MX records, disposable addresses, and mailbox existence, reducing bounce rates.
Solid deliverability: 71.4% inbox placement rate across major providers with automatic suppression lists for bounces and complaints.
Batch sending at scale: Send to 1,000 recipients per API call with recipient variables for personalized bulk emails without exposing recipient lists.
Event logging: Track delivery, opens, clicks, and bounces with detailed logs retained up to 30 days for debugging and compliance.

We hope you enjoyed this shortcut of best email API for Node.js developers. If you want to explore the full version of it, you can visit Mailtrap's blog page!

I Tested 6 Postmark Alternatives: Here’s What I Found

Sofia Tarhonska — Mon, 25 Aug 2025 10:32:13 +0000

Let’s not kid ourselves, Postmark is a great email service in almost every regard. However, if you’re reading this, the chances are that it doesn’t fit your needs anymore, and you’d like to switch it up a little bit.

Luckily, you’ve come to the right place! I’ve interviewed our very own deliverability experts whose opinions are based on the latest state of the industry and years of experience, took their recommendations, tested every platform I mention in this article, and these are the results!

Disclaimer: The references to software ratings, available features, and pricing were valid at the time of writing this article, but could be subject to change in the future.

Best Postmark alternatives: a snapshot

Mailtrap is the best Postmark alternative for product companies with large sending volumes looking for high deliverability and industry-best analytics.
Mailchimp is most suitable for small businesses on a budget who need both email marketing and transactional messaging features.
Mailgun is a solid choice for experienced developer teams since it’s, as its creators say: ‘made by developers, for developers.’
SendGrid offers an email marketing suite and SMTP/API services with rich documentation, but has customer support locked for high-tier plans.
Amazon SES is a great Postmark alternative for experienced developers who are already in the AWS ecosystem.
Brevo is for businesses that want to send transactional emails and do multi-channel marketing.

Here’s a back-to-back free plan and pricing comparison of each Postmark alternative:

Postmark alternatives comparison criteria

Before we get into actual Postmark alternatives, let me share the criteria I’ve used to come up with the list.

I’ll describe the aspects I’ve benchmarked, provide the comparison tables I came up with, and more. This way, you get a 100% unbiased review with no sponsored links or content, just results from many hours of testing.

Email infrastructure

A solid email infrastructure is the backbone of every email service provider out there, and it consists of deliverability, reliability, and scalability.

Deliverability
Every email that doesn’t reach your recipient’s inbox costs you $0.11, so deliverability, or the platform’s actual ability to have your emails land in the main inboxes instead of going to spam or promotion folders, is crucial.

For example, to have your emails hit the mark, Postmark has strict sending policies in place, uses worldwide data centers, provides separate streams, dedicated IPs as add-ons, and a few other bits and bobs.

So, I’ll compare what other providers offer in this regard and what they do to help you reach your recipients’ main inboxes.

I’ll also provide you with deliverability rates some of the providers on this list achieved on our recent deliverability tests we performed using free plans, same templates, and shared IPs. Here are the results:

Reliability
When we’re talking about reliability, we’re talking about whether an email service provider is able to consistently deliver your emails without any major hiccups. Additionally, an ESP shouldn’t face delays or downtimes and should offer transparent monitoring of these issues.

For instance, SendGrid advertises a 99.99% uptime, and I was able to see whether this is actually true by visiting its status page.

Scalability
Scalability is the ESP’s ability to grow with your business, that is, to allow your business to grow without facing bottlenecks, degraded campaign performance, or other major issues.

To be scalable, an ESP should offer some of the following:

High sending throughput
Cloud-based infrastructure
Dedicated IPs or streams
24/7 customer support
Email deliverability consultations

Separate sending stream
As you already know, Postmark offers dedicated sending streams, which you can use to send user-triggered and bulk emails separately.

Now, true separate sending streams are quite rare nowadays, so, on this list, you’ll only see a couple of ESPs that offer them, while the others provide you the tools to separate your streams.

Here’s a quick breakdown of each:

Pricing comparison

To help you decide whether an ESP from this list is more affordable to you compared to Postmark or not, I will break down:

Different pricing plans and features they bring to the table
Price per sent email compared to Postmark
Key pricing differences between each provider and Postmark
And here’s a table for you to get a brief idea of the Postmark alternatives pricing:

Transactional email sending

To help you send transactional emails easily, that is, welcome emails, password resets, etc., Postmark offers an SMTP server with pre-made snippets and a flexible email API.

So, in this article, I’ll list ESPs that offer similarly rich documentation and APIs that support integration with major programming languages. In case you’re an API heavy user and need a plethora of integration options, here’s a breakdown of supported libraries for each provider:

Marketing email sending
Marketing email sending is quite a different story from transactional, since you’re sending campaigns instead of user-triggered messages. Currently, Postmark doesn’t offer this functionality.

In case you’re transitioning because of that, I’ll list some ESPs that can help you optimize your email marketing funnel, namely:

Manage your contacts
Track performance metrics
Perform A/B testing
Automate workflows

Essentially, these are just the features you can use to grow your business via email marketing.

AI, automations, integration
AI in email marketing
AI in email marketing has stopped being a gimmick a while ago. For example, Postmark offers MCP servers, with which you can prompt your AI assistants to send emails, use templates, track performance metrics, or even manage whole campaigns in your stead.

Moreover, ESPs have started integrating AI for audience segmentation, generating subject lines or even email content itself.

So, I’ll make sure to point out useful AI tools I tried and tested throughout the reviews.

Integration

Although Postmark doesn’t offer many integrations, it has several useful ones, like the one with ActiveCampaign, its parent company. You can use it to get some basic email marketing functionality, then pair Postmark with Mailcoach or Craft Campaign to take your campaigns further.

However, if you’re looking for advanced integrations, I’ll be mentioning ESPs on this list that offer them.

Email design

Coding email designs has long been a thing of the past. Most ESPs nowadays offer some of the following features to make your email creation process as seamless as possible:

Drag-and-drop editor – A solid drag-and-drop email builder lets you arrange your email according to your preferences, tweak the layout, preview mobile and desktop versions, and more. Everything without having to go anywhere near your HTML code editor.
Email templates – If an ESP doesn’t offer its own native templates, it at least provides an integration for them. For this article, I checked not only how many template options you get for each ESP but also how good-looking they are.
Sandbox mode – With a sandbox mode, you can safely test your emails before sending them, without worrying that you’ll spam your recipients. So, instead of sending out your emails beforehand, you can just inspect them, see how they fare with spam, and more.

Wrapping up

I hope you enjoyed this comparison of Postmark alternatives, the rest of the article can be found on Mailtrap blog!

How to Send Emails in Claude Desktop with Mailtrap MCP

Sofia Tarhonska — Wed, 06 Aug 2025 17:36:37 +0000

Ever since Mailtrap launched its very own MCP server, Claude can not only generate emails for you, but it can also send them to your recipients.

The integration is super seamless, takes ~5 minutes, and works for both Windows and macOS.

In this guide, I’ll show you how to integrate the Mailtrap MCP, and then we’ll send some emails.

Before we start:

Install the latest Node.js version since Mailtrap MCP is implemented as a Node.js command line utility.
If you haven’t already done so, install the Claude Desktop app. But if you have, make sure it’s updated and uses the latest version.

Setup Mailtrap MCP Server

First, open your Claude Desktop, navigate to Settings, and in the Developer tab, click on Edit Config.

This will open the Claude directory containing the claude_desktop_config.json file. The file is used by Claude Desktop to store the users’ settings and the MCP servers to which you can make requests. We will use it to add a new configuration for Mailtrap MCP.

Tip: You can also open the claude_desktop_config.json file in the following locations:

MacOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json Once you open the claude_desktop_config.json file (e.g., you can do it via any IDE of your choice; personally, I do it via VSC), copy-paste the code snippet below inside it:

{ "mcpServers": { "mailtrap": { "command": "npx", "args": ["-y", "mcp-mailtrap"], "env": { "MAILTRAP_API_TOKEN": "your_mailtrap_api_token", "DEFAULT_FROM_EMAIL": "your_sender@example.com" } } } }

Then, to use Mailtrap API to send emails, open your Mailtrap account and navigate to Sending Domains → Integration → API.

On the Integration/API page, update the following values in your mcp.json file with Mailtrap credentials:

MAILTRAP_API_TOKEN – Used to authenticate API requests, which you can copy/paste from the credentials tab.
DEFAULT_FROM_EMAIL – Make sure the email’s domain matches your own domain from the Sending Domains tab in Mailtrap. Lastly, save the configuration with the updated values and reload Claude Desktop. After reloading, a mailtrap MCP should be present in the Developer Settings.

Send emails with Mailtrap Email MCP Server

To use the configured Mailtrap MCP for email sending, let’s open a new chat.

In the opened window, make sure the MCP tool is specified.

This will allow Claude Desktop to perform actions for us, for instance email sending using Mailtrap MCP and send-email.

Finally, to send a plain-text email, you can use a prompt like the one below, but you can also experiment with your own prompts:

Send an email to john.doe@example.com with the subject ‘Hi John!’ and a message that wishes John a great day.

If Claude asks you to verify the usage of Mailtrap MCP, click Allow for this chat.

Then, it should successfully send a new email and provide you with the properties the email has been sent with in the response.

You can verify it by checking the Email Logs tab of your Mailtrap dashboard.

*Send HTML email *

To send an HTML email in Claude Desktop using Mailtrap MCP, just modify the prompt to clearly state that we want our message to be formatted in HTML. For example:

Send an email to john.doe@example.com with the subject ‘Hi John!’ and a message that wishes John a great day. Make sure the message is nicely formatted by using HTML.

As you send a new prompt, Claude Desktop will send a new email with the html field being specified, which contains the HTML content of our email.

A new HTML email should be sent successfully, which you can verify by checking the Preview tab in Mailtrap Email Logs and see how it looks.

Send email to multiple recipients

To send an email to multiple recipients, all you need to do is specify the addresses you want in the prompt. For instance:

Send an email to Jackie and Michael with a simple greeting. Jackie’s email is jackie@example.com, and Michael’s email is mike@example.com.

As you send a new prompt, Claude Desktop will try to send a new email. In this case, we can see a new cc field being specified, which includes a list of additional recipients provided via carbon copy.

A new email should be sent to multiple recipients, which you can verify by checking the Email Logs tab in Mailtrap.

Wrapping it up

If you enjoyed this article about how to send emails in Claude desktop, you can follow us on Mailtrap Blog where it was first published.

How to Send Emails in Cursor with Mailtrap MCP Server

Sofia Tarhonska — Tue, 05 Aug 2025 17:17:48 +0000

If you want to send emails in Cursor, you won’t be able to do it since it doesn’t have built-in sending functionality. But don’t worry—I’ve got you covered!

In this article, I’ll show you how to integrate Cursor with Mailtrap MCP and start sending emails with simple prompts—whether you’re on Windows or macOS.

Before we start: Since Mailtrap MCP server is implemented as a Node.js command line utility, make sure that besides the Cursor editor, you have the latest Node.js version installed.

Setup Mailtrap MCP Server

First, let’s set up and configure an MCP Server in Cursor. So, open your Cursor editor and navigate to Settings → Cursor Settings.

Once in the Cursor Settings window, go to the MCP tab and click on Add new global MCP server.

This will open a new mcp.json file, which is used by Cursor to store all the MCP servers you can make requests to. Initially, the file is empty, so copy/paste the following configuration inside it:

This setup allows us to use Mailtrap Email API to send emails by prompting the AI within Cursor. However, now you need to replace MAILTRAP_API_TOKEN and DEFAULT_FROM_EMAIL values with your own Mailtrap API credentials.

To do this, open your Mailtrap account and navigate to Sending Domains → Integration → API. There, you’ll see:

Your domain name, which is different for every user. For example, with the domain used for this article, I can use something like ‘no-reply@freelance.mailtrap.link’.
The API token, used to authenticate API requests, which you can copy/paste.

After inserting the credentials in your mcp.json file and saving it, Mailtrap MCP should be successfully displayed as connected in the MCP tab of Cursor Settings.

Note: Although you shouldn’t have issues, we recommend reloading Cursor to make sure everything is set up correctly.

Send emails with Mailtrap MCP server

Now, let’s use the configured Mailtrap MCP to send some emails.

First, toggle the AI Pane, located in the upper-right corner of the Cursor editor.

In the opened pane, make sure that the Agent mode is configured since it allows Cursor to perform actions for us.

To send a plain-text email, you can use a prompt like this one (although I encourage you to use your own prompts and experiment with them since the possibilities are pretty much endless):

Send an email to john.doe@example.com with the subject ‘Hi John!’ and a message that wishes John a great day.

Cursor will then identify the Mailtrap MCP server for your request, suggest running the right tool, in this case, send_email, and generate the email with all the parameters and values for you. As soon as you’re ready to send, click Run tool.

Lastly, Cursor AI will notify you when it successfully delivers the email.

You can verify it by checking the Email Logs tab of your Mailtrap dashboard.

Wrapping it up

We hope you enjoyed reading about sending emails using Cursor and Mailtrap MCP server. This article was originally published on the Mailtrap Blog, where you can find the full version along with many other helpful resources.

Improve Email Deliverability: Here’s How & Best Practices to Follow

Sofia Tarhonska — Tue, 05 Aug 2025 11:08:29 +0000

Hitting the inbox is paramount, no matter how big or small a sender you are.

If not…

Your marketing campaigns go unseen.
Your transactional emails fail to reach their destination.
Your efforts translate into lost revenue and damaged sender reputation.

At Mailtrap, we help you improve deliverability with your organically built audience, whether it’s for marketing campaigns or critical transactional communications.

This comprehensive guide walks you through the essential strategies and best practices that high-volume senders use to achieve optimal inbox placement and maximize their email ROI.

How to improve email deliverability: a snapshot

Achieving high email deliverability is an ongoing process that requires a strategic approach across technical setup, sender reputation, list management, and content optimization.

Here’s a quick overview of the quick wins we’ll explore in detail:

Email deliverability improvement strategies

Achieving consistent inbox placement for your high-volume sends demands a multi-faceted approach.

Email infrastructure setup
Sender reputation
email list quality
email sending
email content quality
email user engagement

I will break down each aspect into an actionable how-to. Let’s start with the technical improvements.

Improve email infrastructure

To improve email infrastructure, you need to focus on email authentication, domain configuration, and email security.

It will show Internet Service Providers (ISPs) and mailbox providers that your emails are legitimate and secure. And actually, all major ISPs require authentication protocols if you’re to be considered a legitimate sender ➡️(Gmail, Outlook, Yahoo, and Apple Mail).

I’ll explain what you should check in your current setup, why this matters, and what steps you need to take to improve your inboxing rates.

Email authentication protocols

Double-check the protocols’ setup and fix the following if you identify any issues.

SPF (Sender Policy Framework): Check your SPF record with Mailtrap’s Free SPF Record Checker. If an email originates from a server not listed in your SPF record, it’s likely to be flagged as suspicious or spam.
DKIM (DomainKeys Identified Mail): Utilize Mailtrap’s Free DKIM Record Checker to validate your setup.
DMARC (Domain-based Message Authentication, Reporting & Conformance) builds on SPF and DKIM. For large senders, it helps gain visibility into spoofing attempts. Use our Free DMARC Record Checker to ensure that DMARC is correctly configured.
BIMI (Brand Indicators for Message Identification): Display your brand’s logo next to your authenticated emails in the recipient’s inbox. While not directly a deliverability protocol, BIMI enhances brand recognition and user trust, indirectly boosting engagement.

For a deeper dive into authentication, refer to our guide on Email Authentication Explained: SPF, DKIM, DMARC, BIMI.

DNS records for email sending

Proper DNS configuration ensures your email servers are correctly identified and email can be routed effectively. So, here’s your homework 😀

rDNS (Reverse DNS or PTR records): Maps an IP address back to a domain name, acting as a “reverse lookup.” ISPs often check PTR records to ensure the sending IP is legitimate and not a generic or dynamic address, which helps prevent spam.
MX records (Mail Exchange records): Specify the email servers responsible for accepting email messages on behalf of your domain. Okay, these are primarily for inbound email, but correctly configured MX records indicate a professionally managed domain, lending credibility to your outbound emails.

Custom domain configurations

Use custom configurations instead of the generic ones provided by your Email Service Provider. Here are the customizations to make.

Custom return path (MAIL FROM): Use a custom subdomain (e.g., bounces.yourdomain.com) for your return path to ensure that bounce handling doesn’t negatively impact your main sending domain’s reputation and allows for easier tracking.
Custom tracking URLs: If your ESP uses tracking links (for opens, clicks), ensure these are branded with your domain (e.g., clicks.yourdomain.com). This avoids sharing reputation with your ESP’s generic tracking domain and instills greater trust in recipients and filters.

Email transmission security standards

Secure emails in transition to protect sensitive data and signal trustworthiness to mailbox providers. This is what to do 🔽

TLS (Transport Layer Security) / STARTTLS: Most ISPs require and prefer TLS connections. You should always enforce STARTTLS where possible.
MTA-STS (Mail Transfer Agent Strict Transport Security): A security standard that forces email servers to use TLS when sending email. It helps prevent downgrade attacks where an attacker might force a connection to use unencrypted channels. Mailtrap’s blog has an in-depth guide on the Mail Transfer Agent (MTA) Explained.
TLS-RPT (TLS Reporting): Companion to MTA-STS, TLS-RPT allows you to receive reports on TLS connection issues, providing visibility into potential security problems that could affect deliverability.

Mailbox provider Feedback Loop (FBL)

Subscribe to FBLs (e.g., through Google Postmaster Tools or Microsoft SNDS) to quickly identify and remove complainers from your list. Of course, this prevents further complaints that damage your reputation.

Email Headers

Properly configured email headers provide necessary information for email servers and can influence how your emails are processed and delivered.

Message ID: Most times, it’s automatically generated. However, ensure it’s correctly formatted and present to help with email tracking and debugging.
Date header: Accuracy here is important for chronological sorting and filter evaluation. So, check these headers particularly if you operate in different time zones.
List-unsubscribe header: Make sure this header provides a one-click unsubscribe option directly within the email client interface. New sender requirements mandate it, and it genuinely helps with spam complaints. Learn more about its importance: List Unsubscribe Header: Why and How to Use.
Precedence header: Used to indicate the nature of an email (e.g., precedence: bulk or precedence: junk) to inform receiving servers that it’s a bulk email and should not generate auto-replies. While less common now, it can still have an impact.

Use a reliable email service provider

If you handle transactional and marketing campaigns at a volume, a reliable Email Service Provider (ESP) is essential. Check whether the ESP provides the necessary technical infrastructure to ensure your emails consistently reach recipients’ inboxes.

For instance, Mailtrap Email API/SMTP offers a robust infrastructure designed for high-volume senders. We focus on maximum throughput and optimal inbox placement by leveraging the following:

Automatic email authentication: Mailtrap configures and manages essential authentication protocols (SPF, DKIM, DMARC). This process verifies your emails as legitimate, significantly reducing the likelihood of them being flagged as spam or rejected by receiving servers.
Dedicated sending streams: Mailtrap provides separate, isolated sending streams for different email types (e.g., transactional vs. marketing). This prevents potential deliverability issues from spilling from one email type to another (marketing to transactional and vice versa).
Robust security and compliance: We are compliant with regulations such as ISO 27001 and GDPR, ensuring your data and your recipients’ privacy are protected.

Wrapping it up

We hope you enjoyed reading about how to improve email deliverability. This article was originally published on the Mailtrap Blog, where you can find the full version along with many other helpful resources.

SMTP vs Email API Explained & Compared: Find Out What Method Developers Should Use

Sofia Tarhonska — Wed, 30 Jul 2025 18:54:04 +0000

A vinyl record and Spotify both get your favorite jams playing, but the way they do it couldn’t be more different. The same applies to SMTP and email API when it comes to sending emails.

SMTP is the underlying protocol that has powered email for decades, while an API is an interface designed to interact with that protocol in a faster, more flexible, developer-friendly way.

In this article, we’ll break down SMTP vs email API — how each works, explore their advantages and limitations, and see which approach is more efficient for your email-sending needs.

SMTP vs email API: a snapshot

SMTP is best for straightforward email sending without requiring complex programmatic control over advanced features. Ideal for systems that send emails like password resets or notifications, as well as legacy platforms. Jump to SMTP →

Email API is designed for modern, scalable applications that require speed and advanced capabilities such as real-time tracking, detailed reporting, and dynamic templates. It works well for high-volume sending, complex transactional messages, and automated workflows.

What is SMTP?

SMTP, short for Simple Mail Transfer Protocol, is the standard protocol used to send emails from one email server to another. It’s been around since the early days of the internet and remains the backbone of email delivery today.

In practice, you’ll often hear the term “SMTP relay”, which generally refers to a third-party service that routes outgoing emails on behalf of your application. Technically, SMTP itself is just the protocol, not the service. However, the term SMTP relay service has become so widely used in the industry that many providers use it interchangeably when talking about sending email through their servers.

The SMTP protocol works by using a series of text-based commands to transfer email messages from a sender’s mail server to the recipient’s server.

So, for example, a typical SMTP session would include commands like:

HELO or EHLO — to introduce the client to the server
MAIL FROM:sender@example.com — to specify the sender’s address
RCPT TO:recipient@example.com — to define the recipient
DATA — to send the email body and headers
Each of the above commands gets a response from the server. This creates a back-and-forth conversation until the message is successfully delivered.

To put this into context, here’s a practical example of sending an email with SMTP in Python using Mailtrap:

Pros of SMTP

Alright, so I’ve covered what SMTP is and how it works. Now, let’s talk about why this decades-old protocol is still relevant in today’s API-driven world. These are the most common reasons teams continue to choose SMTP:

Universal compatibility — Almost every email client, application, and server supports SMTP, meaning you can integrate it into virtually any system without compatibility issues.

Simplicity in setup — Getting started with SMTP is straightforward. All you need are your SMTP credentials (host, port, username, and password), and you’re ready to send emails — no complex coding required.

Proven and reliable standard — SMTP has been around for decades, making it stable, predictable, and well-documented. It works consistently across providers without unexpected surprises.

Works with legacy systems — Older applications and platforms often rely on SMTP as their default email protocol, making it the easiest and most compatible choice for integration without major rewrites.

Broad language and framework support — SMTP libraries are available for virtually every programming language, ensuring smooth integration no matter your tech stack.

Vendor independence — Because SMTP is an open standard, users are not locked into any single provider. Switching typically only requires updating credentials, not rewriting your integration.

Supported by most tools and plugins — Popular CMS platforms like WordPress and Joomla, along with form plugins and e-commerce extensions, often provide built-in SMTP support for quick email configuration.

Easy testing in development environments — SMTP can be quickly configured for staging or QA, making it simple to test email functionality without extra setup or dependencies.

Cons of SMTP

So, it’s clear that SMTP does its job well for basic sending. But as email needs grow more complex, SMTP’s limitations can become evident. Here’s where SMTP struggles the most:

Slower performance for large volumes — SMTP processes each email through multiple sequential commands. This makes it inherently slower, especially compared to APIs optimized for bulk transmission.

Limited scalability — SMTP wasn’t designed for massive email workloads or real-time delivery. Handling high volumes often means managing multiple simultaneous connections and IP pools, which increases complexity and the risk of throttling.

Feature-light by default — Beyond basic delivery, SMTP offers no built-in tools for analytics, reporting, or template management. Adding these features requires additional email infrastructure or third-party solutions.

Vague error handling — SMTP error response codes (like 550 or 421) can be cryptic and inconsistent across providers. This lack of clarity makes diagnosing issues slow and often requires digging through obscure documentation.

Security risks if misconfigured — While SMTP supports TLS, it’s not always enforced by default. Without proper setup, sensitive data and credentials can be transmitted in plaintext, creating compliance and security gaps.

Not cloud-native — SMTP’s design lacks the flexibility needed for microservices and distributed systems. This makes it struggle to adapt to modern containerized or serverless environments without extra configuration.

When to use SMTP

Now that we’ve weighed the strengths and weaknesses of SMTP, the question is: when does it still make sense to use this tried-and-true protocol instead of switching to an API?

Below are some scenarios where SMTP continues to make the most sense:

You’re integrating with a CMS or low-code tool

If your team is using platforms like WordPress, Drupal, or Joomla, or working with popular plugins and form builders, SMTP is often the default method for email delivery. It requires no custom coding — just paste your SMTP credentials into it and start sending. For marketers or non-technical users managing websites, this low-friction setup is a big win.

You’re supporting legacy applications or infrastructure

Older business systems like ERP platforms, internal tools, or CRMs written in languages like COBOL, VB, or older versions of Java, often lack native support for HTTP APIs. Since SMTP is a universally accepted standard, it allows these systems to send emails without a major rewrite, making it the go-to solution for environments that prioritize stability over modern architecture.

Your sending volume is small and predictable

If you’re sending a few hundred emails per day, such as password resets, signup confirmations, or support replies, SMTP handles it with ease. In these cases, you don’t need the scalability or advanced features of an API. SMTP gives you a reliable channel without adding architectural complexity or overhead.

You need a lightweight, temporary setup

For staging, QA, or internal testing environments, SMTP is perfect. It’s easy to connect with test inboxes or mock servers, allowing developers to validate email flows without building out API integrations.

What is an email API?

An Email API (Application Programming Interface) is a modern way to send emails by making HTTP (hypertext transfer protocol) requests to an endpoint of an email service provider. This approach offers speed, flexibility, and advanced functionality that traditional protocols like SMTP don’t offer.

When getting familiar with email APIs, you might also hear the term SMTP API. But, despite their name, SMTP APIs typically don’t replace SMTP itself. Instead, they provide an interface to manage or send emails through an SMTP service. Still, some providers and users treat “SMTP API” and “email API” as the same thing. This, in practice, is incorrect as email APIs are designed for full-featured integrations, not just for routing through SMTP.

During the process of sending emails through an API, your application interacts with the email provider over HTTPS using requests rather than exchanging a series of text-based commands. The structured HTTP requests (usually in JSON) include all the necessary details such as, recipient addresses, subject line, message body, and optional parameters like tracking or templates.

Here are the steps a typical email delivery process via API consists of:

Authenticate using an API token provided by the email service.
Send an HTTP request (usually POST) to the provider’s endpoint with email details in JSON format.

Include additional parameters like HTML email content, templates, tracking options, or attachments if needed.
Receive a response with a status code and detailed delivery info — something SMTP can’t provide out of the box.

A workflow of this type is optimized for delivery speed and scalability and integrates easily into modern applications through official SDKs and libraries.

With Mailtrap’s Python SDK, you can send an email through an email API using the following code:

Pros of email API

So we’ve established that email APIs aren’t just an upgrade; they’re a complete shift in how email delivery works for modern apps. Now, let’s break down some of the pros they bring to developers and businesses:

Speed and efficiency — API requests are lightweight and optimized for high-volume sending, making them significantly faster than SMTP’s step-by-step handshake process.

Feature-rich by design — APIs unlock advanced capabilities like open and click tracking, detailed reporting, dynamic templates, attachments, and even A/B testing, all built into the integration, without extra layers.

Better error handling — Instead of decoding vague SMTP error codes, APIs return structured, human-readable responses, making troubleshooting faster and easier for developers.

Scalability for modern workloads — APIs handle large volumes effortlessly without requiring multiple connections. They’re designed for massive sending, real-time triggers, and automated workflows.

Seamless integration with modern architectures — APIs fit naturally into microservices, mobile apps, and serverless environments. Most providers also offer SDKs for popular programming languages, speeding up development and reducing friction.

Fewer firewall complications — Unlike SMTP, which often requires opening SMTP ports (like 25, 465, or 587) and configuring firewall exceptions, Email APIs communicate over HTTPS (port 443), which is almost always allowed by default. This simplifies deployment and reduces network-related headaches.

Advanced automation support — APIs make it simple to build event-driven or lifecycle-triggered emails directly into your application logic, something SMTP was never designed for.

Cons of Email API

Speed, flexibility, and other advantages that email APIs bring also come with some trade-offs. So, before making the switch, consider these potential drawbacks:

Higher integration complexity — Unlike SMTP, which works almost anywhere with just credentials, APIs require coding, testing, and familiarity with the provider’s documentation. This can slow initial setup, especially for teams without strong dev resources.

Vendor dependency — APIs are provider-specific, so switching services often means rewriting parts of your codebase. Even with SDKs and REST standards, there’s more lock-in than with SMTP’s universal protocol.

Potential cost overhead — For basic use cases, an API can feel like overkill. And if you’re sending just a few password resets or low-volume notifications, the extra development effort (and sometimes pricing structure) might outweigh the benefits.

Learning curve for advanced features — While APIs offer power and flexibility, taking full advantage often requires developers to understand advanced parameters, authentication methods, and integration nuances. This can lead to longer onboarding times and a higher dependency on technical resources.

Security and compliance complexity — APIs often provide more features, but with that comes a bigger responsibility for securing API keys, handling rate limits to prevent abuse, and ensuring compliance with frameworks like GDPR or HIPAA when processing more personal data for tracking and analytics.

Wrapping it up

We hope you enjoyed reading SMTP vs Email API. This article was originally published on the Mailtrap Blog, where you can find the full version along with many other helpful resources.

Choosing the Best SMTP Providers – Top 5 SMTP Providers Compliance Comparison

Sofia Tarhonska — Fri, 25 Jul 2025 17:28:55 +0000

When you manage millions of transactional emails or orchestrate extensive marketing campaigns, the nuances of data protection, privacy, and regulatory adherence can make or break your operations.

This is precisely why you need to hawk over compliance, and set a goal to find a provider that:

Safeguards your data
Respects user privacy
Helps you navigate the labyrinth of GDPR, CCPA, and HIPAA

To help you make an informed decision, I’ll peel back the layers of documentation, from privacy policies and Data Processing Agreements (DPAs) to providers’ infrastructure disclosures and feature sets. My SMTP providers compliance comparison also incorporates:

Insights from practical testing
The visibility of audit logs
The flexibility of account roles
The accessibility of DPAs and
The robustness of data deletion options

SMTP providers compliance comparison: a snapshot

The snapshot gives you an immediate overview of where each provider typically shines and how they initially position themselves regarding compliance.

Truth be told, all the providers listed here are compliant, so it’s not like you’ll make a mistake and choose a service that would somehow jeopardize the legality of your campaigns. But the serve slightly different businesses needs, and Amazon SES, for example, requires expertise to set up.

Anyway, the table below provides a high-level overview. Click on the detailed comparison below for the full analysis.

Methodology

My analysis is built on a two-pronged methodology:

Rigorous documentation review
Practical, hands-on testing

I aimed to make the insights theoretically sound and reflective of real-world functionality for high-volume senders. So, here’s the gist of it.

Documentation research:

Privacy policies: To understand how each provider collects, uses, stores, and protects personal data.
Data Processing Agreements (DPAs): Crucial for GDPR and other privacy regulations, I examined the terms and responsibilities outlined for them as data processors. This included looking for clear commitments on data security, incident response, and sub-processor management.
Infrastructure disclosures: Understanding where and how their data centers operate, their network security, and redundancy measures.
Feature documentation: Specifically looking for features designed to aid customer compliance, such as data retention controls, audit logs, and access management capabilities.

Hands-on testing:

Beyond what’s written, I explored the practical implementation of compliance features within the platforms. This involved:

Audit log visibility: Assessing the detail and accessibility of logs that track user activities and system changes, which are vital for accountability and incident investigation.
Account roles and permissions: Examining the granularity of user roles and how platforms (and users) control access to sensitive data and features. This is essential for adhering to the principle of least privilege.
DPA access and signing process: Evaluating how easily a customer can access and execute a DPA with the provider.
Data deletion options: Testing the mechanisms for customers to permanently delete their data (e.g., email logs, recipient lists) and understanding the retention policies in practice.

With all that, I could present a balanced view, distinguishing between stated policies and their functional implementation. In turn, you get the most relevant insights for your compliance strategy.

SMTP providers compliance detailed comparison

Here, I’ll break down each compliance category, comparing Mailtrap, Mailgun, SendGrid, Amazon SES, and Postmark based on my research and hands-on observations.

Regulations compliance: the global maze 🌎

Before the deep-dive, I’d like to give you the exact context since it’s easy to get lost in all the abbreviations and standards.

When I talk about “regulations compliance”, I’m referring to SMTP providers’ inherent ability and demonstrable commitment to operate within the frameworks of major data protection and privacy laws worldwide.

In my assessment, this means looking at their official stance, available documentation (like DPAs), and features that support your own compliance efforts regarding laws like GDPR, CCPA/CPRA, and, where applicable, HIPAA.

Here’s a direct comparison of how each provider approaches key regulations:

Interpretation:

Here’s my take on what these comparisons mean for you:

GDPR: I look for a clear DPA, transparency about data processing, and features that help me uphold data subject rights (like easy data deletion or access logs).

Mailtrap, Mailgun, SendGrid, and Postmark all offer dedicated DPAs and clear policies, making them solid choices. They provide the necessary contractual framework. Mailtrap’s focus on secure email delivery naturally integrates these principles. For more in-depth info on the subject check: A deeper dive into GDPR and Emails: How to Stay Compliant.
Amazon SES inherits AWS’s compliance. While the underlying infrastructure is compliant, it places more responsibility on you to configure your services correctly for full GDPR adherence. This is suitable for those with strong DevOps teams who want ultimate control, but it might be a steeper learning curve for others.

CCPA/CPRA: If you handle personal information of California residents, these acts are paramount. The focus here is on consumer rights: knowing what data is collected, opting out of its sale, and requesting deletion.

All five providers demonstrate alignment with these principles in their privacy policies and offer features that support your obligations. My review confirms that they understand the need for transparency and control. Again if you need more, check out how CCPA impacts your email strategy at CCPA Email Best Practices.

HIPAA: This one is highly specialized. If your business deals with Protected Health Information (PHI), a Business Associate Agreement (BAA) is a essential.
Mailgun, SendGrid, and Amazon SES explicitly offer BAAs and have well-documented capabilities for handling PHI environments. Amazon SES, being part of AWS, offers an extensive toolkit for building HIPAA-compliant architectures.
Mailtrap doesn’t directy support HIPAA, but we’re ready to review existing BAA of a client.
Postmark doesn’t support HIPAA.

Note: The topic has it’s fair share of intricacies. Therefore, it wouldn’t hurt to check our post on How to Ensure Your Email is HIPAA Compliant?

CAN-SPAM Act: Its core tenets involve clear identification, opt-out mechanisms, and valid sender information. And keep in mind that, while often associated with marketing, CAN-SPAM also applies to transactional emails in certain contexts.

All providers facilitate compliance here by supporting essential email authentication standards like SPF, DKIM, and DMARC, which are critical for sender reputation and deliverability. They also handle aspects like unsubscribe links. Ultimately, ensuring your email content and sending practices adhere to CAN-SPAM is largely your responsibility, but the providers give you the necessary tools.

In essence, while all providers strive for general compliance, the depth of their support and the ease with which you can achieve compliance vary. For high-volume senders, the ability to easily sign a DPA, leverage granular controls, and have transparent data handling practices is a must-have.

Wrapping it up

I hope you found this SMTP providers compliance comparison insightful and interesting. Please note that this article presents only a part of an original and complete analysis published on Mailtrap Blog. Visit us there to explore this topic in more detail!

Which Email API Offers The Most Flexibility: In-Depth Comparison of Best Providers

Sofia Tarhonska — Fri, 25 Jul 2025 09:00:33 +0000

Let’s face it: there is no email API that fits the needs of every team out there. However, a solid API will give you control of your sending process and allow you to fine-tune it according to your team’s requirements.

In other words, an email API needs to be flexible.

So, I’ll break down the email API flexibility for 5 of the best providers out there.

First, I’ll give you a snapshot of my research, tell you about the methodology I used, and then I’ll cover the following components:

Infrastructure and scalability
Sending logic and performance
Integration and extensibility
Templates and personalization
Testing environment
Customer support

Email API flexibility comparison: a snapshot

Mailtrap has the most flexible setup, offers separate sending streams, a full-fledged Sandbox, advanced webhooks, making it great for high-volume senders.
Resend offers great flexibility but lacks some features like dedicated streams, testing solution, and templates, which can be a deal breaker for some.
Postmark is a reliable, minimalistic choice, but if you plan to use it, you’ll have to handle retries, templates, and testing on your own.
Mailgun offers a plethora of advanced features and is quite flexible, although it lacks dedicated streams, and its customer support availability depends on your plan.
SendGrid is a super flexible option for users who are willing to pay for a higher plan for more control of their sending infrastructure.

Methodology

First, I analyzed the official documentation. This includes support portals, knowledge bases, changelogs, and various integration guides from providers, like this one for example.

Going through these docs, I was relatively able to see how easy to use an API is, what it allows me to do, and whether it’s maintained regularly.

Then, of course, I ran tests with each API to simulate real-world usage. By doing this, I was able to see how much control I had over email sending, how easy it is to set up an API, etc. The tests I ran include:

Sending emails with different sending configurations to test real use cases
Triggering rate limits and retry behavior to see how the API handles high volume
Create email templates and see how much personalization they allow
Setting up webhooks for some of the events they support
Using the testing solutions to validate my email designs, check spam scores, etc.

The most important information regarding APIs and the tests I ran is in the following chapter.

Email API flexibility detailed comparison

Infrastructure and scalability

Let’s start off with the essentials, that is, the API infrastructure, for which I considered the following:

Scalability
IP infrastructure
Email streams
Multitenancy support

Scalability

An email API is scalable if it allows you to increase your sending volume without delays, deliverability hiccups, or infrastructure bottlenecks. To allow you all of this, most modern email API providers offer cloud-based infrastructure paired with other features like dedicated IPs.

The following table sums up the technical tidbits related to scalability:

What it means:

Mailtrap offers automatic MTA distribution and help of deliverability experts for setting up your sending configuration. This makes it best for teams who want to scale while having guidance along the way.
Resend adjusts IPs dynamically, meaning the API will adjust to your sending volume in real-time. This makes Resend ideal if you have a fast-growing app with variable sending volumes or a website with traffic spikes.
Postmark distributes email traffic evenly to prevent delays and routes emails through the closest server to the recipient. Thanks to this, it’s considered a reliable choice if you plan to send transactional emails.
Mailgun offers its Rapid Fire Delivery SLA, an agreement promising safe and reliable delivery of up to 15 million emails per hour, delivered under certain pricing plans. This is ideal for senders who plan to perform email blasts.
SendGrid sends emails from servers closest to recipients and combines this with multiple dedicated IPs to ensure stability during spikes.

This makes it best for teams who plan to send both marketing and transactional emails at a high volume.

IP infrastructure

No matter how great your content is or how clean your contact list is, your emails won’t land in the primary inbox if your ESP doesn’t have a solid IP infrastructure, which consists of dedicated IPs, features like auto warm-up, and more.

Here’s a quick breakdown for you:

What it means:

Mailtrap offers free dedicated IPs for senders with a volume higher than 100k/month, has automatic warm up and high-quality shared IPs. This makes it super flexible for teams who plan to scale gradually or send over 100k emails per month.
Resend provides dedicated IPS as an add-on under certain plans, making it perfect for teams who are just starting out and have a low sending volume.
Postmark offers dedicated IPs as an add-on if you’re sending 300k emails/month. It also offers options for managed or self-managed warm-up, which makes it a solid choice for experienced teams, especially smaller senders, since its shared IPs are very reputable.
Mailgun is slightly more flexible with dedicated IPs as an add-on for plans with more than 50k emails per month. It also includes auto warm-up, making it great for inexperienced teams and smaller senders.
SendGrid provides dedicated IPs for free if you’re sending more than 100k emails per month and has auto warm up. This makes it a great choice if you’re looking for a solid API to send marketing and transactional emails.

Email streams

If you plan to send mass emails or different types of emails, having separate sending streams can make a world of difference for your sender reputation. Nowadays, some providers offer a separate infrastructure through IP pooling and dedicated IPs, whereas some also offer a true separate stream.

Here’s a super quick breakdown:

As you can see, only Mailtrap and Postmark have separate sending streams. You can also configure other APIs to do a similar job, but it won’t be as efficient as a true separate stream.

Multitenancy support

If you have several different teams, clients, domains, etc., you’ll need an email API with high-level multitenancy support. Most providers offer multitenancy via subaccounts or sub-users, but some also provide it via servers or domains.

Based on the table:

Mailtrap is best for SaaS platforms or agencies with many clients.
Resend is best for teams who don’t need true multitenancy.
Postmark is best for teams that need to separate clients and apps.
Mailgun is best for those who want to separate tenants between units, clients, or regions.
SendGrid is best for teams with many sender profiles.

Wrapping it up

I hope you enjoyed reading email API flexibility comparison. This article includes selected highlights and was originally published in full on the Mailtrap Blog, which you can visit to read the complete guide.

I Compared 5 Best SMTP Providers for FinTech Companies: Which One Should You Use

Sofia Tarhonska — Fri, 25 Jul 2025 07:57:30 +0000

Reliably sending critical and time-sensitive emails while staying compliant with international data regulation laws is key for any FinTech company out there.

In this article, I’ll provide you with 5 SMTP providers for FinTech that will allow you to achieve all of the above, and more.

To get you started, here’s a snapshot of the platforms, and here’s the methodology and criteria I used to select the providers on this list.

Disclaimer: The references to software ratings, available features, and pricing were valid at the time of writing this article, but could be subject to change in the future.

Best FinTech SMTP providers: a snapshot

Mailtrap is the best email infrastructure for FinTech products that plan to send a high volume of emails with high deliverability rates, in-depth analytics, and growth-focused features.
Mailgun offers a plethora of advanced tech features FinTech, and a solid email API with in-depth documentation.
SendGrid is a reliable transactional email service for FinTech companies with a plethora of quality-of-life features, but the customer support team that prioritizes high-tier users.
Amazon SES is the best SMTP provider for FinTech companies with experienced developer teams who are already AWS users.
Postmark is a minimalistic SMTP provider for FinTech companies that need detailed email logs and can live without any testing features.

For your convenience, here’s a table that sums up the most important points of each SMTP provider:

Why FinTech companies need specialized SMTP provider

Before we proceed with the reviews, let’s quickly go over why you need specialized transactional email services for FinTech in the first place.

Reliability

First and foremost, you need to make sure your transactional emails, that is, payment confirmations, e-invoices, 2FA codes, new device logins, etc., get delivered instantly with no hiccups whatsoever.

Why? Well, they’re tied to real-time user actions, so even a delay of a few seconds can lead to a failed login or an abandoned transaction. This, in turn, loses users’ trust, which is key in FinTech since there is sensitive data in play.

With this, a specialized SMTP provider can help you by offering the following:

High delivery speed (~5 seconds)
Dedicated stream for transactional messages
Flexible retry logic for handling issues like ISP failure
High email uptime with transparent downtime reports

Example use case

You own a neobank, a challenger bank, or BNPL app, and your user needs to receive a one-time password (OTP). If the email with the OTP doesn’t arrive in the user’s inbox, they might face account lockout. So, in this case, you don’t just lose trust, but your customer support team gets more unnecessary work on their hands.

Scalability

Unlike with eCommerce companies, whose emails are a bit static (e.g., cart abandonment emails aren’t sent in blasts), in Fintech, emails can be more dynamic due to market shifts. So, your email infrastructure needs to be scalable in order to withstand new feature emails, regional launches, tax notifications, suspicious activity etc.

That is, an SMTP provider needs to be able to handle the increasing load without any bottlenecks or hiccups. To achieve this, a provider should have:

Cloud-based infrastructure with multiple MTAs
Support for sending high throughput
Dedicated streams or at least dedicated IPs
Deliverability expert support for emergencies

Example use case

You own a crypto exchange, a market cap website, or a trading platform, all of which can acquire a massive number of users in a short time. To register an account, your users need to verify emails, upload documents, connect their digital wallets, make a deposit, etc.

Since the whole account activation process requires you to send them multiple transactional emails, from account confirmations and document approval notifications to welcome emails, your infrastructure needs to be able to withstand the spike in sending volume.

Compliance and auditability

Let’s be honest, if you’re in FinTech, you’re probably knee-deep or at least have been in regulations and compliance. Unfortunately, I have to tell you that there’s a whole lot more of them when it comes to emails.

Namely, since you deal with sensitive information, financial data, or even documents related to identity verification, regulations like GDPR, standards such as PCI DSS, and certifications like ISO 27001 require you to be transparent about user consent, have data protection mechanisms in place, auditable logs, and the list goes on.
Not complying with these usually results in massive fines. Take the CAN-SPAM Act, for instance, which penalizes users for violations with fines of up to $44k per email.

To help you comply with email rules and regulations, and other email marketing laws, an SMTP provider needs to provide you with:

Custom sending domains so you can align with different policies
Proper email authentication to prevent malicious attacks
Detailed event logging that you can use for audits
Clear and transparent data retention policies
Access control and multi-tenancy support for your team
Privacy-first infrastructure with data localization options (i.e., EU-based servers if you’re from EU for regional compliance)

Example use case

You’re sending custom invoices, loan approval, or P2P payments documents that can include sensitive customer information on payment terms, credit scores, etc. To ensure the data doesn’t get into the wrong hands, an SMTP provider needs to enforce TLS and DKIM policies for all outbound emails.

For instance, Mailtrap requires each sender to have proper authentication (SPF, DKIM, DMARC) before they start sending, so each domain is properly checked and prepared.

FinTech transactional email services comparison criteria

Now, let me explain how I came up with the providers on this list and the criteria I used to determine whether they can be the right choice for your FinTech company.

Email infrastructure

Every email deliverability expert out there will tell you that a solid infrastructure consists of four key components: deliverability, reliability, scalability, and separate sending streams.

Deliverability

Email deliverability refers to the SMTP provider’s ability to deliver your emails to your recipients’ inboxes. To achieve a high rate, providers use dedicated IP, have proper IP warmup protocols and authentication, and more. Additionally, they might offer some features to help you increase the performance of your emails as well, such as bounce tracking and inbox placement insights.

However, it’s important to note that deliverability % between providers differs greatly and that sometimes, the advertised deliverability rate also differs from the actual one.

Over at Mailtrap, we wanted to see how big of a difference this is, so we’ve decided to conduct tests with several top SMTP providers for FinTech. To make the tests fair to everyone, we used:

A free-tier subscription
A shared IP environment
Identical email templates across all providers
Seed testing for accurate deliverability testing and tracking

Here’s a table with summarized test results:

Over to you: I know that the deliverability rate can seem like just one more metric, but you should be aware that you lose $0.11 for every undelivered email. And according to our recent research, finance and insurance share the number one spot for landing in spam folders, with a staggering rate of 8.4% of total emails. Not to mention the meager 80% of actual delivered emails and 11.6% of them going MIA.

Wrapping it up

I hope you found this comparison of the top SMTP providers for FinTech companies insightful. Please note that this article presents only a part of an original and complete analysis published on Mailtrap Blog. Visit us there to explore best FinTech SMTP providers in more detail.