OmniDiff Explained: A Syntax-Aware Git difftool in Rust

OmniDiff is a Rust-based Git difftool that reads code as a syntax tree and shows only the parts that actually changed. Where a classic diff marks whole lines as deleted and inserted, it narrows changes down to expressions and even code inside strings. In short, it is worth trying for large refactors and generated-code diffs, but it is an early 0.x release, licensed AGPL-3.0-only, and the author is not accepting outside contributions. Treat it as something to run alongside your current tools, not a new default.

The latest release, v0.3.0, shipped on November 1, 2026, the same day a Show HN post about it collected 143 points on Hacker News. The GitHub repository had 383 stars as of November 2, 2026. Some of the performance and accuracy figures the author publishes still fall short of the stated goals (details below).

OmniDiff builds syntax trees with tree-sitter and highlights only the changed parts. It can be used as an interactive TUI viewer, as plain-text batch output, or as JSON output. The author is Marko Ivankovic, and commit trailers disclose that development uses AI assistance, currently Claude Code. The tool was renamed from CodeDiff to OmniDiff in v0.2.0 on October 1, 2026.

The map above places the tools on two axes. Horizontally, the left is line-based diffing and the right is content (syntax) aware diffing. Vertically, the top is an interactive TUI and the bottom is printed output (a pager or CLI). delta is a line-based pager that makes git's diff easier to read, difftastic is syntax-aware and prints its result to the terminal, hunk is an interactive review viewer built on git's own diff, and OmniDiff combines syntax-aware diffing with an interactive TUI.

The main ways to install are below. Releases also carries prebuilt binaries for Linux, macOS (Intel and Apple Silicon) and Windows. Installing with cargo compiles every tree-sitter grammar from C, so expect a few minutes.

Debian and Ubuntu (amd64 and arm64) have a signed apt repository. Recipes for Arch and Gentoo live in the repository's packaging/ directory.

It is free under AGPL-3.0-only. For internal use inside organizations, a commercial license is available as a monthly GitHub Sponsors subscription; we have not confirmed the amount, so none is listed. Running it as a local tool on your own machine is generally not a problem. If you modify it and distribute it, or offer it over a network, AGPL obligations apply. Before embedding it in a company product, read the LICENSE and consult a professional if needed.

1. Install it (any of the methods above)
2. Register it with Git using omnidiff git configure (choose global or the current repo)
3. Open the interactive TUI with git difftool --tool=omnidiff
4. To look at just two files, run omnidiff before.rs after.rs

One thing to remember: the TUI opens only through git difftool. git diff and git log -p just print plain text and never open the TUI. Inside the TUI, ? lists the keys, o picks files (in the empty viewer you get when launching with no arguments), b toggles half-block and graphics picture rendering, g shows every changed glyph or picture at once, and Enter opens a text member of an archive in a full diff view. For CI, use --headless, --mode json and --exit-code (adds 1 to the exit code when files differ). Exit codes are 0 for success and 2 for an error. Disable color with --color never or NO_COLOR=1; truecolor needs COLORTERM=truecolor.

For Jujutsu (jj), run omnidiff jj configure. Manual setup adds a merge-tools.omnidiff entry and requires diff-invocation-mode set to file-by-file. jj diff renders plain text; to get the full TUI, run omnidiff BEFORE AFTER directly. On the editor side there is a VS Code extension (omnidiff-vscode, also on Open VSX) and omnidiff.nvim for Neovim, but the README says VS Code's built-in diff view cannot be replaced yet.

A practical split: keep delta as the pager for everyday git diff, and open OmniDiff through git difftool only for large refactors. If you want to review AI agent changes with annotations, hunk fits better. difftastic suits people who want syntax-aware results printed to the terminal. Each tool has a different strength, so there is no need to pick just one.

The numbers below are published by the author in the README and were measured on the author's laptop. They are not independently verified.

- Early 0.x software, renamed from CodeDiff at v0.2.0. If you installed under the old name, reinstall and reconfigure
- AGPL-3.0-only: modifying and distributing it, or offering it over a network, carries obligations
- External contributions are closed, so it is effectively a one-person project and its long-term continuity is uncertain
- git diff and git log -p never open the TUI; it opens only via git difftool or a direct run
- VS Code's built-in diff view cannot be replaced yet
- cargo install needs a C compiler and Rust 1.92+, and takes a few minutes to build
- Accuracy goals are unmet, and archives also miss the p99 speed goal
- Markdown, SQL, Protocol Buffers and similar formats are compared as plain text

If you are thinking about reviewing AI agent changes, see Whiteboard and worktrunk, which gives each agent its own worktree. We cover the agent side in the Claude Code complete guide. Note that the author discloses that OmniDiff itself is developed with Claude Code assistance.

- OmniDiff on GitHub
- Releases
- omnidiff on docs.rs