Look first at proven experience, not the size of the portfolio. Request two or three engagements that resemble your domain and your stack, and then find out which engineers actually built it. An honest provider is happy to connect you with the people who would work on your project. Vague answers at this stage almost always mean you are talking to a reseller.

The paperwork warrants more attention than the sales deck. A few clauses carry most of the weight: assignment of intellectual property, confidentiality, and exit terms and handover. All the work product should transfer to you once invoices are settled, including documentation, pipelines and deployment scripts. Look closely at any clause that keeps framework code outside the transfer, since it is usually exactly the piece that locks you in.

Find out how the estimate was built. A serious estimate comes with a written set of assumptions, a task-level breakdown and an explicit range. A fixed price is only reasonable when the specification is complete; when the scope is still moving the provider prices the risk in and you pay for uncertainty either way. A time-and-materials model shifts that risk to you, so it demands visible weekly reporting and build an affiliate platform a spending cap.

The delivery process matters more than team size. Find out what happens when the scope changes, who writes the acceptance criteria and how testing is organised. A team should be able to show you a live build at the end of each sprint. Clear, written acceptance criteria remain the practical protection against an argument at delivery time.

Last, plan for the end of the engagement before it becomes urgent. Insist that the code repository lives ai in custom software development your organisation from day one, and that a readme and architecture notes are kept current as the code changes. A vendor with nothing to hide says yes immediately; a long negotiation over it reveals most of what you need to know.