An estimate that arrives instantly counts as a bad sign. Any serious team returns questions first: about who owns the data and what happens on failure. A supplier that prices without asking anything is simply pricing a guess, and a guess will be corrected later — at your expense.

Watch for a mismatch between the people you meet and the developers actually assigned. Request the names and CVs of the actual team in the agreement, with a provision that requires notice before anyone is swapped. A team that only offers a pool of resources and react native vs flutter will not commit to specific engineers is preserving the option to staff you with whoever is free.

Ask for commit-level visibility from the first week. A team that delivers nothing between demos expects you to trust a black box. Regular commits and pull requests tell you the actual pace far better than a slide deck. The same applies to the automated test suite: if it does not exist, promises about quality remain unverifiable.

Loose phrasing around IP is never an accident. The agreement needs to state in plain terms that all deliverables belong to your business as they are paid for. Check also the governing law and the milestone terms: fintech app development services a request for most of the money up front with no milestone tied to it eliminates the only leverage you have.

Lastly, look at how they communicate. Ask what overlap there will be each day, who answers day-to-day questions and within what time. Some genuine overlap generally works; no overlap stretches a five-minute question into a twenty-four hour round trip. Sloppy written English in the sales phase does not improve under delivery pressure.