Screenshotbot OSS is the open-source release of a commercial visual regression / screenshot testing service. Despite the product branding, it is a genuine polyglot software monorepo whose dominant character is a Common Lisp web application: a Hunchentoot-based server with an in-memory persistent object store (a heavily customized BKNR datastore fork with snapshots, store versioning, checksums, and FSet indexes), server-rendered markup HTML, and a substantial REST API consumed by a companion CLI/SDK. In production it receives screenshot uploads from CI systems (Android, iOS, Selenium, Firebase Test Lab), diffs them via ImageMagick FFI primitives, organizes results into runs/channels/reports, and drives PR/MR review workflows through GitHub, GitLab, Bitbucket, Azure DevOps, Slack/Teams, Phabricator, and task integrations. The repository also contains an OAuth 2.0 authorization server with PKCE/device-flow support, an MCP (Model Context Protocol) server for LLM-driven report triage, an Android Gradle plugin (with an embedded LispWorks runtime), a desktop pixel-diff GUI, and a client-hub/web replay subsystem.