TL;DR
- Your agent (Claude Code, Codex, Cursor…) annotates a PR: a plain-language “why” for each changed block, plus
screenshots, short screen recordings, Markdown reports, CSVs and small interactive HTML demos. Through the skill or the MCP endpoint.
- The notes go to your own DiffNotes server, never to GitHub, GitLab or Bitbucket: no bot comments, no notification noise.
- Reviewers with the browser extension (Chrome, Firefox) see them inside the diff on GitHub, GitLab or Bitbucket: a summary box on top, notes on the
changed lines, image galleries, file previews, what changed since their last visit, one switch to hide everything.
- Notes expire on their own (after a year by default). Files on disk or in any S3-compatible bucket (Backblaze B2, R2, S3, MinIO).
- Up and running in about 5 minutes: one container, one
curl | sh, one extension.
Why
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| Review faster | Reviewers read why a block changed before reading how. Fewer “what does this do?” round trips. |
| Context from the author | The agent that wrote the code explains it while it still knows the decisions and trade-offs. |
| Screenshots in the diff | UI changes come with before/after or mobile/desktop shots next to the lines that caused them. |
| Zero noise | Nothing is posted to the PR. The conversation stays for humans. |
| Your data | Self-hosted, invite-only (or sign-up with GitHub), per-account access. Code context never leaves your infrastructure. |
| Any agent, any team | One skill for every Agent Skills tool; one extension for several servers (teams, clients). |
See it
| On GitHub | |
|---|
| Summary box above the files: the PR's summary, linked reports, a notes on/off switch, expand/collapse all. |
| Gallery: several images in one note (mobile + desktop), ← → to flip, Esc to close. |
| Previews of attached .md, .csv and .txt files, rendered in place. |
| Live demos: a small .html file runs in a locked sandbox under its note (no network, no access to GitHub); expand it at phone, tablet or desktop width. |
| Floating dock once you scroll: note count, notes switch, summary popover. Long notes get show more / less. |
| In the app | |
|---|
| Every annotated PR, with its notes and attachments. |
| Accounts with roles (owner, admin, member), invitations, repositories, storage per repository. |
| Super admin: users, accounts, uploads, disk, and where files are stored. |
Install in 5 minutes
# 1. the server (any Docker host: a VPS, Coolify, Dokku…)
git clone https://github.com/igorkasyanchuk/diffnotes && cd diffnotes
docker build -t diffnotes . && docker run -d -p 3000:3000 -v diffnotes:/data \
-e [email protected] -e PUBLIC_URL=https://reviews.example.com diffnotes
docker logs <container> | grep "first admin" # the generated password
# or: docker compose up -d (docker-compose.yml), or Render / Fly.io / Railway / Coolify: docs/deploy.md
# 2. the skill, on every developer machine (Claude Code, Codex, Cursor, other Agent Skills tools)
curl -fsSL https://reviews.example.com/install.sh | sh
export DIFFNOTES_URL=https://reviews.example.com DIFFNOTES_TOKEN=dn_… # token from /settings
# 3. the extension: https://chromewebstore.google.com/detail/fmnbgmeahjhfakpcmhimjjjplimdiibd
# (or chrome://extensions → Developer mode → Load unpacked → extension/)
# then its popup: server + token → Connect
Then ask your agent: “annotate this PR with diffnotes” and open the PR's Files changed tab. No skills in your agent?
Use the MCP endpoint instead: claude mcp add --transport http diffnotes https://reviews.example.com/mcp --header "Authorization: Bearer $DIFFNOTES_TOKEN" (more).
Docs
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| Install & configure | Docker, environment variables, first admin, password reset, upgrades, backups |
| Deploy | Docker Compose, Coolify, Render (one-click), Fly.io, Railway; one instance only |
| Agent skill | Install, token, how the agent writes notes, payload format, allowed files |
| Browser extension | Install (Chrome, Firefox, Safari), several servers, GitHub / GitLab / Bitbucket, what you see, troubleshooting |
| Accounts & roles | Owner / admin / member, invitations, repository rules, super admin, overview pages |
| File storage | Disk or S3-compatible (Backblaze B2, Cloudflare R2, AWS S3, MinIO), expiry |
| Security | Access model, upload checks, sandboxing, tokens, secrets; report a vulnerability: SECURITY.md |
| API | The HTTP API the skill and the extension use |
| Development | Stack, layout, commands, code rules |
| Changelog |
License
MIT: use it, change it, host it, sell it; keep the copyright notice.
