A quote that comes back within a day should be treated as a warning, not a service level. A competent team will come back with clarifying questions before any number: about integrations. A provider that quotes with no clarification is pricing a guess, and that guess will be corrected later — and you will pay web application development for edtech it.
Look out for any distance between the team in the pitch and the developers actually assigned. Ask for the names and top nodejs development companies CVs of the actual team in the agreement, with a provision about substitutions. A team that will only describe roles and never names specific engineers is keeping its own flexibility at your cost.
Insist on the source repository from the start. A provider that hands over a build only at the end of each phase is asking you to take delivery on faith. Regular commits and pull requests reveal the actual pace far better than a slide deck. The same applies to the build and deployment setup: if it does not exist, what is software development outsourcing promises about quality remain nothing more than words.
Loose wording in the contract around IP is not a formality. The document should state in plain terms that all deliverables transfer to your business as they are paid for. Look too at the jurisdiction and how payments are structured: heavy prepayment with no deliverable attached takes away the only leverage you have.
Finally, examine how they communicate. Confirm how much working-time overlap the teams will share with your working day, who answers day-to-day questions and how quickly. Some genuine overlap is normally sufficient; no overlap turns a five-minute question into a lost day. Careless writing in the proposal rarely improves under delivery pressure.