Originally published at devtoolpicks.com
SendGrid just killed its permanent free plan. Mailgun doubled its pay-as-you-go rate overnight in December 2025. If you're building a SaaS or shipping a side project right now, you're probably rethinking your transactional email setup.
You've got three realistic options that developers actually use in 2026: Resend, Postmark, and Mailgun. I've used all three across different projects. They're not interchangeable. Each one is the right answer for a different stage and a different use case, and picking the wrong one costs you money or costs you delivered emails.
Here's my honest take. No affiliate deals with any of them.
Quick Verdict
| Tool | Best For | Free Tier | Starting Price | Rating |
|---|---|---|---|---|
| Resend | MVPs and React/Next.js apps | 3,000 emails/mo | $20/mo (50k emails) | ⭐⭐⭐⭐⭐ |
| Postmark | Mission-critical transactional email | 100 emails/mo | $15/mo (10k emails) | ⭐⭐⭐⭐⭐ |
| Mailgun | High volume with advanced routing | 100 emails/day | $35/mo (50k emails) | ⭐⭐⭐⭐ |
My pick for most solo devs in 2026: start with Resend. Move to Postmark when your password resets absolutely can't miss the inbox. Consider Mailgun when you need SMTP relay with advanced routing rules and you're sending 50k+ per month.
Resend
Resend launched in 2023 and became the developer darling almost immediately. The team behind React Email built it, and it shows. You write email templates as React components, they render correctly in every client, and the whole thing just works. The API is clean, the docs are modern, and you can be sending emails within 30 minutes of signup.
Pricing:
- Free: 3,000 emails/month (100/day cap, no credit card required)
- Pro: $20/month for 50,000 emails, $0.90 per extra 1,000
- Scale: $90/month for 100,000 emails
- Dedicated IP: $30/month add-on, Scale plan only, requires 500+ daily sends
The free tier is actually worth using. 3,000 emails per month is enough for most early-stage products. The 100/day cap exists but you're unlikely to hit it unless you're doing a launch spike. No expiry date, no credit card.
The developer experience is the best I've used. PHP SDK exists and it's solid, which matters for my Laravel projects. Webhook setup takes two minutes. React Email templates look polished in every client I've tested. Deliverability is solid and improving.
The real cons:
The 100/day cap on the free tier catches people out at the worst possible moment. Do a Product Hunt launch and suddenly 300 people sign up in one afternoon, you're sending 100 welcome emails and dropping the rest. That's a real problem.
Marketing email automation is still maturing. This is a transactional-only tool for most practical purposes. No drip sequences, no lifecycle automation built in. You'll need a separate tool for that.
And if you're not using React or Next.js, you lose the main reason to choose Resend over the alternatives. The API works with any stack, but you're paying a small premium for the DX advantage without getting the template benefit.
Who should NOT use Resend:
If your app handles financial transactions, medical data, or anything where a missed 2FA code means a locked-out user, Resend's deliverability is good but Postmark's is better. If you need enterprise-grade SMTP relay with regex-based routing rules for inbound email, Mailgun handles this differently. If you need multi-tenant sub-account isolation per customer, Resend isn't built for that use case.
Postmark
Postmark is the oldest and most battle-tested of the three. ActiveCampaign owns it now, but it still runs as an independent product with the same developer-first philosophy. Its entire brand promise is simple: your transactional emails will reach the inbox. It largely delivers on that.
In independent testing, Postmark achieves 98.7% inbox placement. Compare that to SendGrid's 95.3% in the same tests. That 3.4% difference sounds small until you do the math. It's 340 extra password resets per 10,000 emails actually getting through. For SaaS products where a missed email means a support ticket and a churned user, the gap matters.
Pricing:
- Free: 100 emails/month (development testing only, never expires)
- Basic: $15/month for 10,000 emails, $1.80 per extra 1,000
- Pro (most popular): $16.50/month for 10,000 emails, $1.30 per extra 1,000
- Platform: $18/month for 10,000 emails, $1.20 per extra 1,000 (unlimited users, servers, streams)
Watch the overages carefully. On the Basic plan, sending 25,000 emails in a month costs $15 + $27 = $42. Upgrading to Pro's lower overage rate pays for itself at around 15,000 emails per month. Most devs should start on Pro, not Basic.
The message streams feature is the best implementation of transactional/broadcast separation I've seen. Transactional and marketing emails run on completely isolated infrastructure with separate sending reputations. If a newsletter bounce rate spikes, your password resets are completely unaffected. That's not possible to replicate on a single shared pool.
Support is identical across all plans including free. Under two hours average response time. That matters when something breaks at 2am before a demo.
The real cons:
The free tier is almost useless for production. 100 emails/month is API testing only. There's a hard cliff between free and the $15 entry point with nothing in between. If you're pre-revenue, that's a real cost that Resend doesn't have.
Overage charges are the highest of the three at lower tiers. Unpredictable volume on the Basic plan gets expensive fast.
Dedicated IPs are locked behind a 300,000 email/month minimum. Most solo devs won't qualify. Their shared IP reputation is excellent, so this rarely matters in practice, but it's worth knowing if IP reputation control is on your requirements list.
No annual discount plans currently available.
Who should NOT use Postmark:
If you're pre-revenue and sending under 3,000 emails/month, the $15 entry point is hard to justify when Resend gives you that volume for free. If you need marketing email automation, CRM features, or lifecycle sequences alongside transactional, Postmark is transactional and broadcast only. If you're a high-volume sender (500k+ per month) on a tight budget, the per-email economics favour alternatives.
Mailgun
Mailgun launched in 2010 and has been through several ownership changes. Sinch owns it now. That history shows in the product: it's powerful, flexible, and complex in ways the newer tools aren't. It was built when developers needed raw email infrastructure control, not a beautiful dashboard.
The big story here is December 2025. Mailgun doubled its Flex pay-as-you-go rate from $1.00 to $2.00 per 1,000 emails. Overnight. No warning. This hit a lot of developers using it for low-volume side projects where irregular sending made pay-as-you-go feel sensible. At $2.00 per thousand, the Flex plan is now more expensive per email than the overage rate on every paid subscription tier. The message from Mailgun is clear: get on a subscription or leave.
Pricing (post-December 2025 changes):
- Free: 100 emails/day (3-month trial only, then paid)
- Foundation: $35/month for 50,000 emails
- Scale: $90/month for 100,000 emails, overage at $0.50/1,000
- Flex (pay-as-you-go): $2.00 per 1,000 emails (up from $1.00 before December 2025)
- EU data residency: +$10/month on any paid plan
The routing rules are the most advanced of the three. If you need to forward, filter, or route inbound emails to different webhooks based on regex patterns, Mailgun handles it in a way Resend and Postmark can't. For products where users reply to emails and you need to parse and act on those replies, Mailgun is the clear choice.
EU data residency is available as a paid add-on. Relevant if you're building for European users who need GDPR-compliant email data handling. No other tool on this list makes EU residency this explicit.
The SMTP relay and API are rock-solid at scale. Reddit uses Mailgun as part of its email infrastructure.
The real cons:
The pricing structure is the most confusing of the three. Foundation plan, Scale plan, a separate Optimize suite for deliverability tools (starting at $49/month extra), email validation billed per address, dedicated IPs billed per IP. You need to read the pricing page twice to understand what you actually get and what's extra.
Subaccount management for multi-tenant products requires Scale plan minimum at $90/month. That's the floor before you've sent a single email.
EU data residency has to be configured at account creation. Migrating existing accounts between regions causes service disruption. It's a trap that catches EU-based developers who don't read the fine print on signup day.
Who should NOT use Mailgun:
If you're early stage and just need basic transactional email, Mailgun is overkill. The Foundation plan at $35/month is 75% more expensive than Postmark for the same or fewer features. If you don't need inbound email parsing, regex routing, or strict sub-account isolation, you're paying for complexity you'll never use. And don't touch the Flex pay-as-you-go plan after the December 2025 price increase. It's the worst value option in this entire comparison.
Head-to-Head Comparison
Here's where your stage matters more than any feature comparison.
Pre-revenue / MVP (under 3,000 emails/month): Resend wins. Free tier, best DX, no credit card. Don't pay anything until you have users paying you.
Early traction ($1k-$5k MRR, 5k-30k emails/month): Postmark at $15-16.50/month beats Resend Pro at $20/month on per-email cost and deliverability. If transactional emails are core to your product's UX, this is the right move. If you're a React shop and DX is your priority, Resend Pro at $20/month is still very reasonable.
Scaling SaaS (50k+ emails/month): Mailgun Scale at $90/month gets you 100,000 emails at $0.50/1,000 overage, the cheapest overage rate of the three. But Resend Scale is also $90/month for 100,000 emails. If you need advanced routing or inbound parsing, Mailgun wins at this tier. If you don't, Resend or Postmark at similar pricing with better DX wins.
Here's a decision flow for picking your tool:
flowchart TD
A[Need transactional email?] --> B{Monthly send volume?}
B -- Under 3k/mo --> C[Resend Free Tier]
B -- 3k to 50k/mo --> D{What matters most?}
D -- DX plus React Email --> E[Resend Pro at $20/mo]
D -- Inbox placement above all --> F[Postmark Basic or Pro at $15-16.50/mo]
B -- 50k+ per month --> G{Need inbound routing or parsing?}
G -- Yes --> H[Mailgun Scale at $90/mo]
G -- No --> I[Resend or Postmark Scale tier]
Final Recommendation
If you're building your first SaaS or side project: start with Resend. Free tier is the best, DX is the best, and you're live in an afternoon.
If your product is live and transactional emails are core to your UX (password resets, booking confirmations, anything where a missed email is a lost user): switch to Postmark. Pay the $15-16.50/month. The deliverability difference is real, the support is excellent, and the message streams isolation is a feature you'll appreciate as you scale.
If you're sending 50,000+ emails per month and need inbound email parsing, regex-based routing, or strict per-tenant sub-account isolation: Mailgun Scale is the right tool. Accept the complexity and the higher learning curve.
Whatever you choose, don't use Mailgun's Flex pay-as-you-go plan after the December 2025 price doubling. It's now more expensive per email than every other option at any volume.
One more thing worth mentioning: your hosting setup matters too. If you're running on a VPS like Hetzner rather than managed hosting, verify your server IP isn't on any blocklists before pointing a production domain at it. That's a fast way to hurt deliverability no matter which API you're using. Once your email is sorted, picking the right payments stack is the other early SaaS infrastructure decision that catches founders off guard.
FAQ
Is Resend good for Laravel?
Yes. Resend has an official PHP SDK and integrates cleanly with Laravel's mail configuration. You swap out Mailgun for Resend in config/mail.php in about 10 minutes. The React Email advantage is lost if you're not building templates in React, but the API and deliverability work just as well with any stack.
Which has the best deliverability: Resend, Postmark, or Mailgun?
Postmark leads on deliverability. Independent tests show 98.7% inbox placement versus around 95-96% for Resend and Mailgun. For most solo dev projects the gap is small enough to ignore. For products where transactional emails drive core UX or compliance, the difference is worth paying for.
Does Postmark have a free plan worth using?
No. The free developer plan is 100 emails/month, which is API testing only. If you need a real free tier for production, use Resend's 3,000 emails/month and migrate to Postmark once you're generating revenue.
What happened to Mailgun's free plan?
Mailgun dropped its generous 10,000 free emails/month plan back in 2020. Today the free tier is 100 emails/day for a 3-month trial only. After that you're on a paid subscription or the Flex pay-as-you-go rate at $2.00 per 1,000 emails. It's not competitive for free usage anymore.
Can I use these tools with PHP or Laravel, not just JavaScript?
Yes. All three offer REST APIs and SMTP relay that work with any language or framework. Resend has an official PHP SDK. Postmark has SDKs for PHP, Ruby, Python, Go, and more. Mailgun has always had strong PHP support. The React Email advantage is specific to Resend's templating layer, not to the sending infrastructure.
Conclusion
The transactional email market shifted in late 2025. SendGrid pricing changes pushed developers to look for alternatives, and Mailgun's Flex rate doubling confirmed that cheap pay-as-you-go email APIs are gone.
For most indie hackers and solo developers building SaaS in 2026: Resend for free and early stage, Postmark when deliverability matters, Mailgun when you need routing power at high volume. All three are solid. Pick the one that matches where you are today, not where you hope to be in two years.
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