A quote that comes back within a day counts as a bad sign. Any serious team will come back with questions first: about who owns the data and code audit services what happens on failure. A provider that quotes without asking anything is simply guessing, and that guess becomes a change request later — on your budget.
Watch for any distance difference between symfony and spring boot the engineers on the sales call and those who eventually appear in the repository. Request specific people rather than roles software development company in germany the agreement, with a provision that requires notice before anyone is swapped. A vendor that talks only about a pool of resources and never names people is reserving the right to assign anyone it likes.
Require the source repository from day one. A partner that shows a build only at the end of each phase is inviting you to take delivery on faith. Regular commits and pull requests tell you the actual pace far better than any status report. The same applies to the build and deployment setup: if nothing runs automatically, assurances about quality are nothing more than words.
Ambiguous phrasing around IP is not an oversight. The contract should state explicitly that all deliverables transfer to the client on payment. Also check which country’s law applies and the payment schedule: heavy prepayment with nothing due in return for weeks eliminates any leverage you would otherwise keep.
Last, examine communication. Confirm how many hours the teams will share with your timezone, which person handles questions and within what time. Four hours of overlap is usually enough; none at all turns a five-minute question into a lost day. Sloppy written English in the early emails rarely improves once the work starts.