Look first at relevant experience, not the number of logos on the website. Ask for three or four case studies that resemble your stack, and then ask whether those engineers are still with the company. An honest provider is happy to connect you with the people who would work on your project. Evasive answers at this stage almost always mean you are talking to a reseller.
The agreement warrants a slower read than the pitch. Three clauses do most of the work: intellectual property assignment, the NDA, and termination and handover. All the work product should transfer to you as it is paid for, together with designs, custom rust development scripts and infrastructure configuration. Be careful with any clause that leaves framework code outside the transfer, as it is usually the dependency that makes switching painful.
Ask how they estimate. A credible estimate is accompanied by the assumptions behind it, a task-level breakdown and a best case and a worst case. A fixed price only makes sense when the requirements are stable and documented; hire developers in russia any other case the vendor pads the number and you pay for it anyway. Hourly billing moves the risk back to the client, so it requires a sprint cadence, demos and blockchain development company a budget cap.
The delivery process beats team size. Establish what happens when the scope changes, who writes the acceptance criteria and what the QA setup looks like. A team should be able to walk you through a working build every one livewire or react two weeks. Acceptance criteria in writing are the only reliable protection against endless rounds of rework.
Last, consider the day you no longer need this vendor while the relationship is still good. Ask that the code repository sits 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; a long negotiation over it says quite a lot.