Begin with relevant experience, not the number of logos on the website. Request a couple of case studies that sit close to your stack, and then ask whether those engineers are still with the vue development company. An honest provider is happy to connect you with the engineers. Evasive answers at this stage generally mean the delivery team is not the team you were shown.

The contract needs more scrutiny than the proposal. A few clauses carry most of the weight: intellectual property assignment, confidentiality, next js development agency and exit terms and handover. Everything produced should transfer to you once invoices are settled, together with designs, scripts and infrastructure configuration. Look closely at language that keeps framework code with the vendor, as it is usually the part you cannot replace later.

Ask how they estimate. An honest estimate comes with a list of assumptions, a breakdown per feature and a range rather than a single number. A fixed-price contract only makes sense when the specification is complete; when the scope is still moving the supplier prices the risk in and rag vs langchain you fund the buffer regardless. A time-and-materials model moves the risk back to the client, so it needs a cap, regular demos and transparent reporting.

How the work is run beats the number of developers. Find out how a new requirement enters the plan, who signs off on a feature and what the QA setup looks like. A well-run team should be able to show you a live build at the end of each sprint. Written acceptance criteria stay your only real protection against an argument at delivery time.

Finally, think about the day you no longer need this vendor at the start rather than at the end. Insist that the repository lives under your account from the first commit, and that documentation is written as you go rather than left to the end. A vendor with nothing to hide accepts it without argument; resistance at this point says quite a lot.