A quote that comes back within a day is a warning, not a service level. Any serious team returns clarifying questions before any number: outsource java development about who owns the data and what happens on failure. A supplier that commits to a figure with no clarification is simply guessing, and the gap will be corrected later — and you will pay for it.
Be wary of any distance between the people you meet and the developers actually assigned. Ask for named engineers in the contract, with a clause covering replacement. A vendor that will only describe abstract roles and refuses to name specific engineers is keeping the option to staff you with whoever is free.
Require the source repository from the start. A partner that hands over nothing between demos is inviting you to accept a black box. Regular commits and pull requests show you who is really on the project far better than a weekly report. This extends to the build and deployment setup: if it does not exist, assurances about quality remain unverifiable.
Ambiguous phrasing around IP is rarely a formality. The document must state in plain terms that all deliverables transfer to your aso company in usa upon settlement of the relevant invoice. Look too at the jurisdiction and how payments are structured: a large upfront payment with no milestone tied to it eliminates any leverage you would otherwise keep.
Last, pay attention to the working rhythm. Establish how much working-time overlap the teams will share with your timezone, who answers day-to-day questions and on what response times. A few hours of overlap is usually enough; no overlap converts every clarification into a lost day. Sloppy written English in the proposal will not improve under delivery pressure.
