Start with domain experience, not the length of the client list. Request a couple of engagements that match your domain and your custom software development stack, and llm integration services then ask specifically who actually wrote that code. An honest provider will introduce you to the tech lead. Vague answers at this stage usually mean you are talking to a reseller.
The contract warrants more scrutiny than the proposal. Three clauses do most of the work: assignment of intellectual property, confidentiality, and notice periods and handover. Everything produced must transfer to you as it is paid for, together with source code, vuejs vs reactjs designs and infrastructure as code. Watch for wording that keeps framework code in the vendor’s hands, as this is frequently the dependency that makes switching painful.
Ask where their numbers come from. A serious estimate arrives with a list of assumptions, a breakdown per feature and an explicit range. A fixed-price contract is only reasonable when the scope is genuinely frozen; in any other case the provider pads the number and you pay for it anyway. Time and materials shifts that risk to you, so it demands visible weekly reporting and a spending cap.
The delivery process matters more than headcount. Establish how a new requirement enters the plan, ai integration services who defines done and how testing is organised. A team will be able to show you a working build every one or two weeks. Written acceptance criteria remain your only real protection against the it-was-never-in-scope conversation.
Last, plan for the end of the engagement at the start rather than at the end. Ask that the code repository lives under your account from the first commit, and that a readme and architecture notes are kept current as the code changes. A vendor with nothing to hide says yes immediately; resistance at this point tells you a great deal.