The single largest cost driver is not the choice of framework — it remains uncertainty. Every ambiguity in the requirements turns into padding in the estimate. A vendor that has no visibility into what happens on the unhappy path will assume a pessimistic case. Spending a week on requirements work can cut the overall figure by far more than negotiating the rate.
Connections to other systems remain another reliable source of cost. A form that saves data is easy to estimate; the same screen connected to a payment provider and laravel vs django comparison a CRM is another matter entirely. The cost lives in the other system: undocumented APIs, long certification processes, data that does not match your model. Ask each bidder to break integrations out as separate items, as this is the usual source of overruns.
The requirements nobody writes down silently change the number. An internal tool used by a small internal team has almost nothing in common with the same idea handling thousands of external customers. Compliance work, uptime targets, scalability, audit logging and accessibility all add measurable effort. State them early or else expect the estimate to move later.
The team you are quoted changes the arithmetic. A day rate reveals little on its own: one senior react developer for hire at twice the price is often cheaper per delivered feature than a pair of junior developers who require constant review. Ask as well who else is billed: project management, quality assurance, DevOps and UX design are real work, but they should be named rather than hidden inside a blended rate.
The number in the proposal is not what you will actually spend. Plan for hosting, paid APIs, monitoring and a maintenance allowance for every year the industry specific software development runs. A reasonable rule of thumb holds that a live system consumes a meaningful share of the initial investment per year simply to stay current. Treating the launch as the finish line remains the most common budgeting mistake.