The biggest cost driver is not the technology stack — it remains uncertainty. Every open question in the brief turns into padding inside the number you receive. A supplier that does not know the exceptions and edge cases will assume a pessimistic case. Spending a week on a discovery phase can cut the overall figure far more than haggling over hourly rates.

Connections to other systems tend to be another reliable source of mvp development cost. A screen that writes to your own database is predictable; the same screen wired into a legacy ERP is not. The cost hides in the counterparty: rate limits and sandbox access, slow approval cycles, data that does not match your model. Ask each bidder to break integrations out as separate items, since this is where estimates break.

Quality attributes silently change the budget. An application used by a small internal team costs far less than the same functionality serving thousands of external customers. Security reviews, availability guarantees, scalability, audit logging and multi-language support each add real engineering time. Write them down at the start or you can expect the estimate to move later.

The team you are quoted matters a great deal. An hourly rate tells you very little on its own: one senior hire protobuf developer at twice the price can be cheaper overall than two juniors who need supervision and rework. Ask as well who else is billed: coordination, QA, infrastructure work and UX design are legitimate costs, but they must be itemised.

The quoted figure is not the full cost of ownership. Expect hosting, third-party licences, monitoring and an ongoing support budget each year. A reasonable rule of thumb says that a live system needs a recurring percentage of the original budget every year for updates, security patches and small improvements. Leaving it out of the budget remains the classic mistake.