10 questions to ask before hiring an agency

1. What similar projects have you completed? Look for specific examples with measurable outcomes. Generic portfolio pieces aren't enough.
2. Can you give us references from those projects? If an agency won't, that's a red flag. Always call the references.
3. What's your process for requirements gathering? If they're ready to quote a fixed price after one meeting, they're guessing.
4. How do you handle scope changes? Look for a written change-request process and transparent pricing per change.
5. What happens if the project goes over budget or timeline? Understand who bears the cost. "We'll work it out" means you bear it.
6. Who, by name, will actually work on my project? Senior salespeople aren't always the ones writing the code. Get the rate per role in writing.
7. What's your approach to testing and QA? Testing should be in the process, not at the end. Ask for the test pyramid they actually run.
8. How will you document the system? Documentation determines whether you're locked in. ADRs, runbooks, and architecture diagrams should be deliverables.
9. What's included in post-launch support? Launch is the beginning, not the end. Get the warranty period and the SLA in writing.
10. Why this technology stack for my project? Good answers reference your needs and constraints. Bad answers reference the agency's preferences.

The shape of a good answer is concrete and bounded. "We did a similar project for X, here is the architecture diagram, here is the launch metric, here is the contact you can call." The shape of a bad answer is generic and aspirational. "We follow agile best practices and partner closely with our clients." If you can't picture the deliverable from the answer, the answer is marketing.

Pay attention to who answers. If every question goes to the salesperson and never to a technical lead, you are buying a sales process, not engineering. Ask to speak with the developer who would actually build your system. Their candor will tell you more than the proposal will.