Look first at domain experience, not the length of the client list. Request two or three projects that match your domain and your stack, and then ask which engineers actually built it. A solid partner will introduce you to the people who would work on your project. Evasive answers at this stage usually mean the demo work came from somewhere else.

The agreement deserves more attention than the sales deck. A few clauses carry most of the weight: ownership of the code, non-disclosure, and notice periods and handover. All the work product should transfer to you once invoices are settled, together with designs, scripts and infrastructure configuration. Look closely at wording that keeps reusable components in the vendor’s hands, since it is usually the part you cannot replace later.

Ask how they estimate. A credible estimate is accompanied by a list of assumptions, a breakdown by feature or module and a range rather than a single number. A fixed-bid deal only makes sense when the specification is complete; otherwise the vendor pads the number and you fund the buffer regardless. Time and materials puts the risk on your side, so it needs a cap, regular demos and transparent reporting.

Process beats team size. Ask how a new requirement enters the plan, web development services company who writes the acceptance criteria and vue.js development services what the QA setup looks like. A mature team will be able to show you a working build every one or two weeks. Written acceptance criteria remain the practical protection against the it-was-never-in-scope conversation.

Last, think about the end of the engagement while the relationship is still good. Require that the code repository lives under your account from the beginning, and that documentation is updated as part of the work. A partner who is comfortable with this will agree quickly; a long negotiation over it tells you quite a lot.