Visual regression before every release

Screenshot diffs before every release, and why partial results mattered more than a perfect diff.

Four days from an empty repository to a screenshot-based QA service: a Lambda driving a headless browser, state in DynamoDB, a two-stage error handler.

The decision that paid off was partial results. A run of hundreds of pages will always have a few that time out; if the whole run fails on the first one, nobody looks at the rest.

Takeaway

Report what was captured and list the misses. That is what made the tool something the release actually waited for.

Client engagement, 2021 to 2026. Names, identifiers and internals are generalised.