Look first at proven experience, not the size of the portfolio. Request three or four projects that sit close to your stack, and then ask specifically whether those engineers are still with the company. A solid partner will put you on a call with the people who would work on your project. Vague answers at this stage generally mean you are talking to a reseller.

The agreement needs a slower read than the pitch. Three sections matter more than the rest: intellectual property assignment, the NDA, and termination and handover. All the work product should transfer to you once invoices are settled, along with designs, scripts and infrastructure configuration. Watch for any clause that leaves reusable components outside the transfer, since this is frequently exactly the piece that locks you in.

Ask how they estimate. A credible estimate is accompanied by a written set of assumptions, a task-level breakdown and a range rather than a single number. A fixed price is only reasonable when the requirements are stable and documented; when the scope is still moving the provider prices the risk in and you pay for uncertainty either way. A time-and-materials model puts the risk on your side, so it needs a cap, regular demos and transparent reporting.

How the work which is better flutter or react native run matters as much as the number of hire pytest developers. Ask what happens when the scope changes, hire a dedicated development team who defines done and how quality assurance works. A team will be able to walk you through running vue js software rather than status reports. Acceptance criteria in writing stay your only real protection against endless rounds of rework.

Before signing, plan for the end of the engagement before it becomes urgent. Require that the code repository sits on infrastructure you own from the beginning, and that the documentation is refreshed in every sprint. A provider confident in its own work accepts it without argument; a long negotiation over it reveals most of what you need to know.