The single largest cost driver is never the choice of framework — it is unclear scope. Each unanswered question in the brief turns into a buffer inside the number you receive. A vendor that cannot see the exceptions and edge cases must assume the more expensive option. Spending a week on a proper discovery frequently cuts the final cost far more than any rate negotiation.
Connections to other systems tend to be the second big multiplier. A feature that touches only your own data is easy to estimate; the same screen connected to an old accounting system is a different problem. The effort lives in the other system: poor documentation, waiting on someone else’s team, inconsistent data. Ask the estimator to break integrations out as separate items, as that is where the numbers slip.
The requirements nobody writes down can easily double the estimate. An web application development for edtech used by a handful of staff is a very different build from the same feature set handling a hundred thousand users. Compliance work, high availability, load handling, audit logging and multi-language support add measurable effort. Write them down at the start or else expect the estimate to move later.
The dedicated vs outsourced software development team you are quoted changes the arithmetic. An hourly rate tells you almost nothing on its own: an experienced engineer at a premium rate frequently turns out to be cheaper overall than two juniors who require heavy code review. Also ask who else is billed: delivery management, QA, infrastructure work and analysis are legitimate costs, but they must be named rather than hidden inside a blended rate.
The quoted figure is rarely the total cost. Budget for hosting, subscriptions and russia software development agency licences, monitoring and a change budget annually. A useful planning figure is that affiliate software development company in active use needs a noticeable fraction of its original build cost per year for updates, security patches and small improvements. Ignoring this is the most frequent planning error.