The biggest cost driver is rarely the choice of framework — it remains how much is still undecided. Every open question in the requirements turns into padding somewhere in the quote. A supplier that cannot see the exceptions and edge cases has to assume a pessimistic case. Putting two weeks into a proper discovery can cut the total far more than haggling over hourly rates.
Connections to other systems tend to be another reliable source of cost. A screen that writes to your own database is low risk; the same screen connected to an old accounting system is another matter entirely. The cost sits in the third party: undocumented APIs, waiting on someone else's team, inconsistent data. Ask the estimator to list every external system, as this is the usual source of overruns.
The requirements nobody writes down silently change the estimate. A tool used by a small internal team is a very different build from the same idea handling thousands of external customers. Security reviews, availability guarantees, performance under load, audit logging and multi-language support each add weeks of work. State them early or else expect them to arrive later as change requests.
The team you are quoted changes the arithmetic. A rate card reveals very little on its own: top react native development companies one senior developer at a premium rate is often less expensive in the end than two juniors who require supervision and rework. Ask as well which roles are billed: project management, testing, dedicated team php DevOps and reactjs vs vuejs analysis have to be done by someone, but they must be visible in the estimate.
The number in the proposal is not what you will actually spend. Budget for hosting, paid APIs, observability and an ongoing support budget for every year the enterprise software development with java runs. A reasonable rule of thumb holds that any production system requires a meaningful share of the initial investment every year in fixes, updates and small changes. Ignoring this has always been the classic mistake.
