Twigg

Twigg is an open-source reimplementation of Google's internal code-review platform Critique — the workflow Google engineers use daily. It is explicitly not a Git wrapper: the entire version-control system is written from scratch in Go (~96K lines, 439 Go files across five binaries). AGPL-3.0 licensed.

Twigg is opinionated about one scenario: collaboration in closed teams. It bakes in trunk-based development and small stacked commits as the default rather than a discipline people must remember. Around that core it adds hierarchical code ownership (OWNERS files that cascade down directories), code review built for stacked changes that evolve version by version, and integrated CI/CD that runs on the trunk and triggers only on modified paths.

The monorepo contains five binaries plus a shared storage/VCS core:

• tw — the CLI (clone, commit, amend, rebase, submit, pull/push)
• twigg-web — the web server hosting repos, review, docs, and CLI binaries
• twigg-track — the job scheduler ("the server in which the runners run")
• twigg-runner — the job executor (Docker or LXD/VMs)
• twigg-vscode — a VSCode extension

Storage is a from-scratch engine shared by client and server: an append-only "datastrip" log for blob bytes with a SQLite index (modernc.org/sqlite, pure Go), delta-encoding consecutive blob versions. Commits are versioned (amend/rebase/submit produce a new version of the same logical commit, not a new commit), which is what makes "review version by version" possible.

The repo is a read-only GitHub mirror; actual development happens on Twigg's own hosted instance (dogfooding). The mirror snapshot is at Twigg commit c/1341 (2026-08-12).