GamStop is a free, government approved self exclusion service designed to help people take control of their gambling. Operated under the auspices of the UK Gambling Commission, GamStop creates a central record that is shared with UK licensed online gambling operators. When a person enrolls, their profile is flagged and access to registering new accounts or continuing to play gambling sites not on gamstop on licensed sites is blocked for the chosen exclusion period. The aim is to reduce the ease of engaging with regulated online gambling, to support people who are worried about their gambling habits, and to align with wider responsible gaming duties that operators owe their customers and communities. Exclusion periods can be 6 months, 1 year, or 5 years, with indefinite inclusion if the person chooses. The system itself is not a punishment; it is a safety tool. It does not apply to offshore or non licensed operators outside the UK, so some players might still gamble with sites that do not participate in GamStop, though those sites may carry higher risk and fewer protections. GamStop relies on collaboration with licensed operators who integrate its database at the point of account creation. If someone tries to sign up on a UK license site after GamStop registration, the operator should decline the account automatically. If a user already has an account before registration, it should be blocked from new activity on UK licensed sites during the exclusion. In addition, GamStop excludes participation across payment services on those sites to reduce the risk of fast access again. Understanding these basics helps players decide if GamStop meets their needs and how to continue with responsible gambling while staying safe.