build an affiliate platform estimate that arrives instantly counts as a warning, not a service level. Any serious team will come back with questions first: about who owns the data and government it software what happens on failure. A vendor that prices with no clarification is simply working from a template, and the gap resurfaces as a change order — at your expense.
Look out for a gap between the team in the pitch and the developers actually assigned. Request named engineers in the statement of work, with a provision that requires notice before anyone is swapped. A provider that only offers roles and refuses to name specific engineers is preserving its own flexibility at your cost.
Ask for the source repository from day one. A provider that delivers nothing between demos is asking you to accept a black box. Daily commits tell you how many people are really working far better than any status report. The same holds for the automated test suite: if there is no pipeline, quality claims are nothing more than words.
Vague wording in the contract around IP is not a formality. The contract should state explicitly that the code, designs and documentation belong to the client as they are paid for. Look too at the governing law and vue js or angular the milestone terms: heavy prepayment with nothing due in return for weeks removes any leverage you would otherwise keep.
Lastly, examine how they communicate. Confirm how much working-time overlap the teams will share with your timezone, which person handles your questions and within what time. A few hours of overlap generally works; zero overlap converts a five-minute question into a twenty-four hour round trip. Careless writing in the sales phase does not improve once the work starts.