GitHub - moritzwilksch/diffle: A keyboard-first diff viewer with LSP support and GitHub integration.

Review a Git diff in the browser and comment on lines, blocks, or whole files. Then hand the comments to an agent as a prompt, or to GitHub as a pending review.

Install

pixi global install diffle               # conda-forge
npm install -g @moritzwilksch/diffle     # npm

Or grab the standalone binary, which needs no Node.js. On Linux (x64, arm64, glibc) and Apple silicon macOS:

curl -fsSL https://diffle.app/install.sh | sh

It installs to ~/.local/bin. Set DIFFLE_INSTALL_DIR to change that, or DIFFLE_VERSION=v0.1.9 to pin a release. On Windows (x64, arm64), from PowerShell:

irm https://diffle.app/install.ps1 | iex

To try it without installing:

pixi exec diffle working
npx @moritzwilksch/diffle working
nix run github:moritzwilksch/diffle -- working

The Nix package bundles gh; #minimal drops it, and #web, #rust, and #python bundle language servers.

Pick what to review

diffle                  # HEAD vs worktree, like a bare `git diff`
diffle working          # HEAD vs worktree: staged, unstaged, untracked
diffle develop          # what this branch added since it left develop
diffle pr 27            # GitHub PR 27, or its URL; without a number, this branch's PR
diffle show a1b2c3d     # one commit, like `git show`
diffle main..feat       # any git-diff revspec: <rev> | a..b | a...b | a b
diffle main..worktree   # "worktree" names the uncommitted tree on either side
diffle range-diff main..v1 main..v2   # how a series of commits was reworked, like `git range-diff`
diffle --help           # all commands and flags

diffle pr needs a GitHub token. A PR from another repository opens in a temporary clone.

Closing the last diffle tab stops the server and prints your open comments. Pass --keep-alive to keep it running.

Review

j / k: next or previous line (10j: ten lines down)
J / K: next or previous file
] / [: next or previous hunk
c: comment
C: comment on the whole file
V: select a block
R: resolve
v: mark viewed
/: search the current file
g/: search all changed files
gf: filter files
F: open the full file
Ctrl+o: go back
yy: copy all comments

Press ? for the full list.

A comparison lists its commits above the threads. Pick one, or step with < and >, to see that commit alone; All changes returns to the whole range. Comments on a focused commit belong to that commit, as in diffle show.

Comments live in <git-dir>/diffle/ and never touch your worktree. They follow their text as the code changes and go stale once it leaves the diff.

Generated files start collapsed, as on GitHub: linguist-generated in .gitattributes marks them, and linguist-generated=false opts a file out. To collapse other files, add auto-viewed globs in settings or with diffle config.

Send comments to GitHub

The pull request icon adds one thread, or all open threads, to a pending review on the PR. diffle never submits it: you edit, drop, and submit the comments on GitHub yourself. Adding a thread again updates its comment instead of duplicating it.

Export works when the comparison matches the PR's committed diff, so unpushed commits and worktree changes rule it out. Stale threads are skipped.

diffle takes the token from GITHUB_TOKEN, then GH_TOKEN, then a signed-in gh. Without one, everything except GitHub still works. GITHUB_API_URL points diffle at another GitHub API, as in Actions.

Jump to definitions

diffle starts a language server for each language in the diff, if it finds one on PATH:

gd or Ctrl/Cmd+click: definition
gy: type definition
gA: references
gs / gS: file or repository symbols
gh: hover, including schema docs for JSON, YAML, and TOML
w / b / 0 / $: step through a line's symbols; the one under the cursor or the pointer is tinted wherever it recurs in the file, writes apart from reads

Results outside the diff, such as the standard library, open read-only. Large repositories can take a while to index.

diffle lsp shows which server each language gets and what to install for the rest:

python    pyrefly lsp
rust      not on PATH (tried rust-analyzer)

Override a server or turn one off:

diffle config set-lsp rust "rust-analyzer"       # persistent
diffle config set-lsp java ""                    # never start one for java
diffle config unset-lsp rust                     # back to PATH
diffle working --lsp python="pyrefly lsp"        # this run only
diffle working --no-lsp                          # none at all

Language servers run through a shell inside the repository and can read anything your user can. --no-lsp starts none.

Shell completions

diffle completion --shell bash > ~/.local/share/bash-completion/completions/diffle
diffle completion --shell zsh > ~/.local/share/zsh/site-functions/_diffle   # on fpath, before compinit
diffle completion --shell fish > ~/.config/fish/completions/diffle.fish

Rerun after upgrading to pick up new commands. Revisions don't complete.

Behind a reverse proxy

diffle works under a path prefix such as https://proxy.example/diffle/ with no extra setting. Have the proxy strip the prefix, including for WebSocket upgrades at /diffle/ws, and trust its public origin:

diffle working -H 0.0.0.0 --no-open --allowed-origin https://proxy.example

If the proxy rewrites Host and Origin to its upstream address, such as a Kubernetes service name, trust that address instead. A rejected request gets a 403 naming the header that failed.

Development

npm install
npm run dev -- working
npm test && npm run typecheck && npm run build

Restart npm run dev after client changes; the server serves dist/client. npm run fixture -- <dir> builds the repository the tests review, covering renames, binaries, CRLF, and more. Screenshot tests run in Docker so they match CI:

npm run test:e2e:docker                  # the browser suite
npm run test:e2e:docker -- -g search     # matching scenarios
npm run test:e2e:report                  # open the last report
npm run test:e2e:docker:update           # accept new screenshots

See AGENTS.md for more.

Acknowledgements

diffle is inspired by difit. Diffs are rendered with @pierre/diffs.