Start with domain experience, not the number of logos on the website. Ask to see two or three projects that sit close to your stack, software development agency and then ask specifically who actually wrote that code. An honest provider will introduce you to the engineers. Evasive answers at this stage generally mean the delivery team is not the team you were shown.
The agreement needs a slower read than the pitch. Three sections matter more than the rest: intellectual property assignment, the NDA, and notice periods and handover. Every artifact should transfer to you as it is paid for, including source code, designs and infrastructure as code. Watch for language that keeps framework code in the vendor’s hands, as 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 an explicit range. A fixed-bid deal is only reasonable when the scope is genuinely frozen; otherwise the provider pads the number and hire react native experts you pay for uncertainty either way. Time and materials shifts that risk to you, so it requires a sprint cadence, demos and a budget cap.
How the work is run beats team size. Find out what happens when the scope changes, who signs off on a feature and how testing is organised. A well-run team should be able to demonstrate running software development outsourcing models rather than status reports. Acceptance criteria hire developers in saudi arabia writing are the practical protection against an argument at delivery time.
Finally, plan for the day you no longer need this vendor before it becomes urgent. Ask that the code repository lives on infrastructure you own from the first commit, and that a readme and architecture notes are kept current as the code changes. A vendor with nothing to hide will agree quickly; resistance at this point says quite a lot.