Testing plays a critical role in the development of your web site and its long-term maintenance. Web testing is a collection of related activities with a single goal to uncover errors in web content, function, usability, navigability, performance, capacity, and security.While smaller web sites— especially those with more limited budgets—may not need to follow the formal testing procedures that are required for large-scale, commercial web sites, every site needs to be thoroughly tested to ensure that it's error-free, user-friendly, accessible, and standards compliant.

Testing should be completed during each phase of a site's development. Testing during production makes it easier to locate and resolve errors, and minimizes the chance of existing bugs being replicated throughout later stages of development.