What Actually Drives Software Development Costs
The dominant factor is not the choice of framework — it is almost always unclear scope. Every open question in the requirements becomes a contingency in the estimate. A supplier that cannot see the edge cases will assume the worst. Putting two weeks into a discovery phase can cut the total far more than any rate negotiation.
Connections to other systems remain another reliable source of cost. A screen that writes to your own database is low risk; the same screen wired into a payment provider and a CRM is a different problem. The unknown hides in the other system: rate limits and sandbox access, waiting on someone else's team, data that does not match your model. Ask each bidder to list every external system, since this is the usual source of overruns.
The requirements nobody writes down can easily double the estimate. An application used by a handful of staff costs far less than the same idea serving public traffic. Compliance work, high availability, performance under load, traceability and accessibility each add measurable effort. Write them down at the start or expect them priced as extras.
Who actually does the work matters. An hourly rate tells you very little on its own: a senior engineer at twice the price frequently turns out to be cheaper per delivered feature than a pair of junior developers who need constant review. Ask as well which roles are billed: delivery management, QA, top aso agencies infrastructure work and UX design are real work, but these should be named rather than hidden inside a blended rate.
The number in house team vs outsourcing costs the proposal is never what you will actually spend. Budget for infrastructure, third-party licences, observability and a change budget flutter developer for hire every year the software runs. A useful planning figure holds that software development for healthcare in active use requires a noticeable fraction of the initial investment every year for updates, security patches and small improvements. Leaving it out of the budget remains the most frequent planning error.