Who will actually do the work?
Ask to meet the developers, not just the salesperson. Find out if the team is in-house or subcontracted, and whether the same people stay for the whole project.
How do you handle changes?
Every project changes. A good partner explains clearly how new requests are estimated, approved and billed, before any surprise invoice arrives.
How will I see progress?
You should see working software every week or two, not a big reveal at the end. Ask for demo calls and access to a test version from the start.
Who owns the code?
Make sure the contract says you own everything that is built, and that the code lives in an account you control.
What happens after launch?
Bugs, updates and small improvements continue after go-live. Ask what support looks like, how fast they respond and what it costs.
Can I talk to a past client?
A confident partner will happily connect you with someone they have worked with. Ask that client what went wrong and how it was handled.
What would you not build?
The best partners push back. If they agree with every idea, they are selling, not advising.