User Acceptance Testing
Also known as: UAT
User Acceptance Testing (UAT) is the final validation phase where real or representative end users test the software against their actual business needs, deciding whether it's ready for release. It's typically the last gate before go-live, run after all internal testing is already complete.
UAT is deliberately run by the people the software is actually for — business stakeholders, end users, or a client — rather than QA engineers, because its purpose is validation (did we build the right thing) not verification (did we build it correctly), and only the actual users can really answer the first question.
A UAT cycle usually runs against real-world business scenarios rather than pre-written technical test cases, and a formal sign-off from the participating users is often the literal gate that unblocks release — making UAT as much a business and communication process as a testing one.
