Look first at domain experience, not the size of the portfolio. Ask to see two or three projects that resemble your domain and your stack, and then find out which engineers actually built it. An honest provider will put you on a call with the tech lead. Vague answers at this stage generally mean the demo work came from somewhere else.

The agreement needs more attention than the sales deck. Three sections matter more than the rest: assignment of intellectual property, the NDA, and termination and handover. Everything produced has to transfer to you as it is paid for, including documentation, pipelines and deployment scripts. Watch for wording that leaves reusable components outside the transfer, because this is frequently the part you cannot replace later.

Ask where their numbers come from. A serious estimate arrives with a list of assumptions, a breakdown by feature or module and an explicit range. A fixed price only makes sense when the specification is complete; otherwise the provider adds a risk premium and you pay for uncertainty either way. A time-and-materials model moves the risk back to the client, so it requires visible weekly reporting and a spending cap.

The delivery process matters as much as headcount. Ask how a new requirement enters the plan, who signs off on a feature and how quality assurance works. A well-run team will be able to walk you through running in house vs outsourcing software development rather than status reports. Clear, written acceptance criteria stay the only reliable protection against endless rounds of rework.

Last, plan for the handover at the start rather than at the end. Ask that the repository lives under your account from day one, custom ai development services and that documentation is updated as part of the work. A partner who is comfortable with this says yes immediately; hesitation here reveals most of what you need to know.