What Really Drives Custom Software Development Cost
The dominant factor is not the choice of framework — it is uncertainty. Every ambiguity in the requirements is converted into a buffer somewhere in the quote. A team that cannot see what happens on the unhappy path will assume a pessimistic case. Putting two weeks into a discovery phase can cut the total by far more than negotiating the rate.
Connections to other systems remain the next major multiplier. A form that saves data is easy to estimate; the same functionality talking to a legacy ERP is a different problem. The effort sits in the other system: alpine js vs livewire rate limits and smm agency sandbox access, slow approval cycles, data that does not match your model. Ask the estimator to list every external system, since this is where estimates break.
Quality attributes quietly rewrite the budget. An application used by twenty people is a very different build from the same feature set handling public traffic. Security reviews, high availability, performance under load, audit logging and accessibility each add real engineering time. Write them down at the start vue or angular else expect the estimate to move later.
The team you are quoted changes the arithmetic. An hourly rate tells you very little on its own: a senior engineer at a higher rate frequently turns out to be less expensive in the end than a pair of junior developers who need supervision and rework. Ask as well what else appears on the invoice: delivery management, testing, DevOps and analysis are real work, but these should be visible in the estimate.
The number in the proposal which is better symfony or spring boot rarely the total cost. Plan for hosting, third-party licences, observability and a change budget for every year the software runs. A common working assumption is that a live system consumes a meaningful share of the original budget every year in fixes, updates and small changes. Leaving it out of the budget has always been the most frequent planning error.