A number produced without questions should be treated as a bad sign. A competent team will come back with clarifying questions before any number: why hire a dedicated team instead of freelancers about who owns the data and what happens on failure. A supplier that commits to a figure with no clarification is working from a template, and flutter development company a guess resurfaces as a change order — on your budget.
Be wary of a mismatch between the people you meet and those who eventually appear in the repository. Ask for named engineers in the agreement, with wording about substitutions. A provider that only offers abstract roles and never names specific engineers is preserving the right to assign anyone it likes.
Require commit-level visibility from day one. A team that hands over a build only at the end of each phase is asking you to take delivery on faith. Daily commits show you the actual pace far better than a slide deck. The same applies to the build and deployment setup: if it does not exist, quality claims remain nothing more than words.
Loose contract language around intellectual property is never an oversight. The document needs to state explicitly that all outputs produced under it become the property of the client on payment. Check also the governing law and how payments are structured: heavy prepayment with no milestone tied to it removes any leverage you would otherwise keep.
Lastly, pay attention to the working rhythm. Ask how many hours you will share each day, which person is expected to answer your questions and laravel or ruby on rails what response times. A few hours of overlap is usually enough; none at all converts every clarification into a twenty-four hour round trip. Sloppy written English in the early emails does not improve later.