UAT (user acceptance testing) and sign-off
The final check where the buyer’s own users test the delivered software against agreed criteria and formally accept it, which often triggers payment.
Contracts set how long the buyer has to test, how defects are classified and which ones block acceptance. Many include deemed acceptance: if the buyer does not report blocking defects within the window, or starts using the software in production, it counts as accepted. UAT is the buyer’s work, and teams often forget to plan people’s time for it.
Related terms
- Definition of Done: A shared checklist of what must be true before work counts as finished: tested, reviewed, deployed, documented.
- Change request (change order): A formal request to change agreed scope, with its own estimate of cost and time, that both sides approve before the work starts.
- Hypercare and warranty period: Hypercare is extra support right after go-live; the warranty period is the time the vendor fixes its own defects for free.
- Pilot success criteria (exit criteria): Measurable conditions agreed before a pilot starts that decide whether it passed and the buyer moves to a full contract.
