Look first at proven experience, not the number of logos on the website. Request three or four case studies that match your domain and your stack, and then find out which engineers actually built it. An honest provider will introduce you to the people who would work on your project. Vague answers at this stage usually mean you are talking to a reseller.
The contract warrants a slower read than the pitch. A few clauses carry most of the weight: assignment of intellectual property, the NDA, and exit terms and typescript web framework handover. Every artifact has to transfer to you as it is paid for, along with designs, scripts and infrastructure configuration. Watch for wording that leaves so-called reusable libraries in the vendor's hands, since this is frequently the part you cannot replace later.
Find out how the estimate was built. An honest estimate comes with a list of assumptions, a task-level breakdown and a range rather than a single number. A fixed price is only reasonable when the specification is complete; in any other case the supplier prices the risk in and you pay for uncertainty either way. A time-choosing between laravel and node js-materials model shifts that risk to you, so it needs visible weekly reporting and a spending cap.
How the work is run matters more than headcount. Ask what happens when the scope changes, who signs off on a feature and how quality assurance works. A team should be able to show you a live build at the end of each sprint. Clear, written acceptance criteria are the only reliable protection against the it-was-never-in-scope conversation.
Last, consider the end of the engagement before it becomes urgent. Ask that the repository sits under your account from the beginning, and that a readme and architecture notes are kept current as the code changes. A vendor with nothing to hide accepts it without argument; resistance at this point tells you most of what you need to know.
