The biggest cost driver is never technology — it remains how much is still undecided. Each unanswered question in the requirements becomes a buffer somewhere in the quote. A vendor that has no visibility into the exceptions and edge cases has to assume the more expensive option. Spending a week on a discovery phase often reduces the total much more than haggling over hourly rates.

Integrations tend to be the second big multiplier. A screen that writes to your own database is predictable; the same feature connected to a legacy ERP is another matter entirely. The effort lives in the other system: poor outsourcing project team documentation, long certification processes, data that does not match your model. Ask each bidder to list every external system, as this is the usual source of overruns.

Quality attributes can easily double the number. A tool used by twenty people costs far less than the same idea serving a hundred thousand users. Compliance work, high availability, load handling, traceability and localisation add real engineering time. State them early or you can expect the estimate to move later.

The mix of people behind the number matters. A day rate tells you very little on its own: one senior igaming developer at twice the price is often cheaper overall than a pair of junior developers who require constant review. Check too which roles are billed: delivery management, QA, DevOps and analysis have to be done by someone, but they should be itemised.

The quoted figure is rarely the full cost of ownership. Expect infrastructure, third-party licences, monitoring and a maintenance allowance annually. A useful planning figure says that any production system needs a meaningful share of the original budget annually for updates, security patches and small improvements. Leaving it out of the budget is the most frequent planning error.