February 26, 2026
Diff wars, deploy your side
Show HN: Deff – side-by-side Git diff review in your terminal
New terminal tool ‘Deff’ sparks a diff war — old guard vs shiny toys
TLDR: Deff is a new terminal app that shows code changes side‑by‑side without an editor. The comments split between “stick with delta/icdiff or vimdiff” and “there’s room for a lightweight reviewer,” with wishes for inline comments and shout‑outs to difftastic’s smarter comparisons — a classic new‑tool vs habit showdown.
A new Rust-made terminal app called Deff just burst onto the scene promising side‑by‑side views of code changes, colorful highlights, and speedy keyboard moves — and the comment section immediately turned into a diff war. For context: a “diff” is how coders see what changed between files, and a TUI is a simple text app you run in the terminal. Deff aims to make that easier without opening a full-blown editor. But the crowd came ready. Longtime users swore loyalty to icdiff. The pragmatists argued you should just hook a tool into Git’s built‑in pager and keep your usual commands, shouting out delta. And the old guard slammed down one line like a mic drop: vimdiff.
The hottest debate? Adoption vs. novelty. One top comment warned that learning “new incantations” is a hard sell, while another admitted there’s real space for a clean, side‑by‑side reviewer on remote servers where you can’t run a heavy editor. Feature wishlists showed up fast too: a user wants GitHub‑style inline comments right in the diff. Meanwhile, the “galaxy brain” camp hyped difftastic for comparing code by understanding its structure, not just lines. Jokes flew about the name (“my name is deff,” cue the rap intro) and the eternal truth that “Vimdiff never dies.” Verdict: it’s fresh vs. familiar, and that tension is the real show.
Key Points
- •Deff is a Rust-based terminal UI for side-by-side interactive Git diff review.
- •It supports upstream-ahead and explicit range comparison strategies, with an option to include uncommitted and untracked changes.
- •Features include independent pane scrolling, keyboard/mouse and Vim-like navigation, in-diff search, and per-file reviewed state persisted under .git.
- •Installation is via a curl-based script that uses Cargo; local builds and Cargo installation are supported.
- •A GitHub Actions workflow publishes tagged releases with Linux/macOS artifacts and SHA256 checksums; documentation includes an architecture guide.