Look first at domain experience, not the size of the portfolio. Ask to see three or four projects that match your stack, and then ask specifically which engineers actually built it outsourcing russia. A solid partner will introduce you to the engineers. Evasive answers at this stage generally mean you are talking to a reseller.
The contract warrants more attention than the sales deck. A few clauses carry most of the weight: ownership of the code, non-disclosure, nearshore outsourcing and exit terms and handover. Every artifact should transfer to you once invoices are settled, including source code, designs and infrastructure as code. Watch for language that leaves framework code outside the transfer, since it is usually the dependency that makes switching painful.
Find out how the estimate was built. A credible estimate comes with a written set of assumptions, a breakdown by feature or module and an explicit range. A fixed price only makes sense when the requirements are stable and documented; when the scope is still moving the provider pads the number and you pay for it anyway. Time and materials puts the risk on your side, so it requires a cap, regular demos and transparent reporting.
The delivery process beats team size. Establish what happens when the scope changes, who writes the acceptance criteria and how quality assurance works. A team should be able to walk you through running software rather than status reports. Written acceptance criteria are the only reliable protection against endless rounds of rework.
Finally, think about the end of the engagement at the start rather than at the end. Require that the source repository lives under your account from the beginning, and that the documentation is refreshed in every sprint. A partner who is comfortable with this will agree quickly; hesitation here says most of what you need to know.
