The dominant factor is rarely the choice of framework — it is almost always uncertainty. Each unanswered question in the requirements turns into a buffer somewhere in the quote. A team that cannot see the exceptions and llm development company edge cases will assume the worst. Investing a few days in a proper discovery often reduces the overall figure far more than any rate negotiation.

Connections to other systems remain the second big multiplier. A feature that touches only your own data is easy to estimate; the same screen talking to a payment provider and a CRM is not. The effort lives in the counterparty: undocumented APIs, slow approval cycles, fields that mean something different on each side. Ask any vendor to price integrations separately, as this is the usual source of overruns.

Non-functional requirements can easily double the budget. An internal tool used by a small internal team is a very different build from the same idea handling public traffic. Compliance work, uptime targets, scalability, audit logging and localisation all add weeks of work. State them early or you can expect them to arrive later as change requests.

Who actually does the work matters a great deal. A day rate tells you very little on its own: an experienced engineer at a premium rate is often cheaper per delivered feature than two juniors who need heavy code review. Also ask which roles are billed: coordination, edtech web development testing, infrastructure work and UX design have to be done by someone, but they must be visible in the estimate.

The build price is not what you will actually spend. Expect hosting, third-party licences, monitoring and a change budget each year. A common working assumption is that a live system requires a meaningful share of the original budget annually for updates, security patches and small improvements. Treating the launch as the finish line is the most common budgeting mistake.