Start with proven experience, not the number of logos on the website. Ask to see a couple of case studies that resemble your domain and your stack, and then ask who actually wrote that code. A serious vendor 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 agreement deserves a slower read than the pitch. Three clauses do most of the work: assignment of intellectual property, the NDA, and exit terms and handover. All the work product should transfer to you on payment, together with designs, scripts and infrastructure configuration. Watch for language that leaves reusable components outside the transfer, because it is usually exactly the piece that locks you in.

Ask how they estimate. A credible estimate is accompanied by a written set of assumptions, a breakdown per feature and a range rather than a single number. A fixed price which is better laravel or .net only reasonable when the scope is genuinely frozen; otherwise the supplier adds a risk premium and you pay for uncertainty either way. Hourly billing puts the risk on your side, so it needs a sprint cadence, demos and a budget cap.

The delivery process beats headcount. Find out how a new requirement enters the plan, who defines done and how testing is organised. A mature team should be able to demonstrate running software rather than status reports. Clear, written acceptance criteria stay the only reliable protection against the it-was-never-in-scope conversation.

Before signing, plan for the day you no longer need this vendor before it becomes urgent. Insist that the source repository stays on infrastructure you own from day one, vue.js vs react.js and that documentation is updated as part of the work. A partner who is comfortable with this says yes immediately; a long negotiation over it reveals quite a lot.