Happo

Happo is a visual regression and accessibility testing service. It renders your components and pages in real browsers on every commit and shows what changed. With the Happo connector, Claude can find the Happo comparisons for a commit, read every diff, added, and deleted snapshot, and look at the before and after images itself. It sees how much each diff changed and where, and which accessibility rules a change newly breaks, with a screenshot of the failing element. It can also read the render logs to explain why a snapshot looks wrong, such as an image that was still loading. Because Claude already knows what your change was meant to do, it can tell intended changes from regressions: accept the diffs you meant, reject the ones you didn't with a note your reviewers see, and report flaky snapshots so they stop coming back. Every action is attributed to you and respects your account's review permissions. Happo never needs access to your repository: Claude brings the context, Happo brings the diffs.