We have all been there. Management signs a multi-year contract for a shiny new enterprise software platform. They hand it over to the engineering team to integrate, only for you to discover the "API" is a messy SOAP endpoint, the documentation is a 40-page PDF from 2016, and there is no staging environment.
Bad software procurement doesn't just waste money; it drains engineering resources and crushes developer velocity.
Whether you are an AI engineer looking for a new vector database, or a tech lead evaluating an observability platform, choosing B2B software is as much an engineering decision as it is a business one.
To save you from integration nightmares, we've put together the ultimate SaaS vendor evaluation checklist. Here are the 15 critical SaaS vendor questions you need to ask before signing on the dotted line.
API, Data, and Developer Experience (DX)
If you can't integrate with it easily, it is not worth buying. A solid B2B SaaS comparison must start with Developer Experience.
1. Is the platform API-first, and what are the rate limits?
You need to know if the UI features are actually accessible via the API. Furthermore, you need to understand how the vendor handles rate limiting. Are limits exposed via standard HTTP headers (X-RateLimit-Remaining)?
// A quick sanity check script to evaluate a SaaS vendor's API limits
async function evaluateSaaSApi(endpoint, apiKey) {
try {
const response = await fetch(endpoint, {
headers: { 'Authorization': `Bearer ${apiKey}` }
});
// A good B2B SaaS will expose rate limits in headers
const limit = response.headers.get('X-RateLimit-Limit');
const remaining = response.headers.get('X-RateLimit-Remaining');
console.log(`Rate Limit: ${limit}, Remaining: ${remaining}`);
if (!response.ok) {
throw new Error(`Vendor API failed with status ${response.status}`);
}
return await response.json();
} catch (error) {
console.error("Evaluation failed: Bad DX detected.", error);
}
}
2. Do you support webhooks or event-driven architectures?
Polling APIs is inefficient. You need to know if the vendor supports outbound webhooks, EventBridge integrations, or Kafka streams to push data into your existing architecture.
3. Does it have an interactive sandbox or staging environment?
Never buy enterprise software if you cannot test it safely. Ask if they provide a dedicated sandbox environment that mirrors production without billing you for test transactions.
4. How easy is it to export our data?
Vendor lock-in is a real threat. A crucial part of technology vendor selection is knowing your exit strategy. Ask for the exact API endpoints or processes required to bulk-export your data in standard formats (JSON/CSV).
Security, Auth, and Compliance
Security isn't a feature; it's a prerequisite. Add these to your software procurement checklist to keep your CISO happy.
5. Do you hold active SOC 2 Type II or ISO 27001 certifications?
Don't just ask if they are "compliant." Ask for the actual attestation report. If they are handling your customers' PII, this is non-negotiable.
6. Is SSO (SAML/OIDC) supported natively, or is there an "Enterprise Tax"?
Many SaaS vendors lock Single Sign-On (SSO) behind their most expensive tiers. Ask upfront what it costs to integrate with your identity provider (Okta, Auth0, Entra ID).
7. Where is the data hosted, and do you offer data residency options?
If you are operating in regions with strict data privacy laws (like the EU's GDPR), you need to know if the vendor allows you to strictly host data in specific AWS/GCP regions.
8. How are secrets and encryption handled?
Ask how they handle encryption at rest (e.g., AES-256) and in transit (TLS 1.2+). If the platform requires storing your API keys to third-party services, ask how those secrets are vaulted.
Reliability and Infrastructure
You are outsourcing a piece of your system's reliability to a third party. Make sure they can handle the load.
9. What is your historical uptime, and where is the public status page?
A vendor claiming 99.99% uptime means nothing without receipts. Ask for their historical status page and check how they handled their last major outage.
10. What happens when we exceed our tier limits?
Do they hard-throttle your API requests (breaking your app), or do they allow overages and bill you at the end of the month? Graceful degradation is a must.
11. Can we automate infrastructure provisioning?
If your team uses Infrastructure as Code (IaC), ask if the vendor maintains an official Terraform provider, Pulumi packages, or a robust CLI tool.
12. What are your Disaster Recovery (DR) and backup protocols?
If the vendor's primary database goes down, what is their Recovery Time Objective (RTO) and Recovery Point Objective (RPO)?
Support and Business Viability
The best technology vendor selection goes beyond code. It's about a long-term partnership.
13. What level of support do engineers actually get?
When a complex bug arises, developers don't have time to battle a Level 1 support chatbot. Ask if enterprise tiers include a dedicated technical account manager or direct Slack/Discord access to their engineering team.
14. How are breaking changes communicated?
Check their API versioning strategy. Ask how much notice they provide before deprecating an endpoint (the industry standard is at least 6 months).
15. What does the 12-18 month product roadmap look like?
This gives you insight into whether they are investing in the features your engineering team cares about, or simply building marketing widgets.
Final Thoughts
Running through this SaaS vendor evaluation checklist before signing a contract will save your engineering team countless hours of frustration. The best B2B SaaS tools act as force multipliers for your developers, seamlessly integrating into your stack and scaling with your product.
Take this software procurement checklist to your next vendor meeting, ask the hard technical questions, and build with confidence.
Originally published at https://getmichaelai.com/blog/your-b2b-saas-vendor-evaluation-checklist-15-questions-to-as
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