Look first at relevant experience, not the size of the portfolio. Request three or four engagements that sit close to your domain and your stack, and hire node expert then ask who actually wrote that code. A solid partner is happy to connect you with the people who would work on your project. Answers that name nobody at this stage usually mean you are talking to a reseller.
The paperwork deserves more scrutiny than the proposal. Three clauses do most of the work: assignment of intellectual property, non-disclosure, and termination and handover. Everything produced must transfer to you on payment, together with documentation, pipelines and deployment scripts. Be careful with wording that keeps reusable components with the vendor, since this is frequently the dependency that makes switching painful.
Find out how the estimate was built. A credible estimate comes with a written set of assumptions, a task-level breakdown and outsource kubernetes development an explicit range. A fixed-price contract works only when the scope is genuinely frozen; when the scope is still moving the vendor prices the risk software development company in uae and you fund the buffer regardless. A time-and-materials model puts the risk on your side, so it requires a cap, regular demos and transparent reporting.
Process matters as much as the number of developers. Establish what happens when the scope changes, who writes the acceptance criteria and how quality assurance works. A mature team can walk you through a working build every one or two weeks. Clear, written acceptance criteria are your only real protection against the it-was-never-in-scope conversation.
Finally, plan for the handover while the relationship is still good. Insist that the repository lives in your organisation from day one, livewire development services and that a readme and architecture notes are kept current as the code changes. A partner who is comfortable with this will agree quickly; hesitation here says quite a lot.