Codiff is a lightweight desktop diff viewer that lets developers inspect staged and unstaged Git changes before committing. Built for speed, the app renders large diffs in under a minute and offers file filters and a search bar, giving reviewers quick access to the exact lines that changed.

The tool supports a unique LLM‑generated walkthrough mode triggered with codiff -w. By feeding a diff to an on‑device language model, Codiff produces a guided review in minutes, even for thousands of lines. Reviewers can copy the full Markdown output, including context, back into their preferred LLM for follow‑up analysis.

After the initial release, the author added inline comment support and a terminal helper that exposes a codiff command. The macOS installer is available on the release page, and users can install the helper via Codiff > Install Terminal Helper. The project remains open source, encouraging forks and community contributions.

Codiff targets developers who routinely review large language‑model‑generated code. By marrying a lightweight desktop UI with AI‑driven commentary, the tool streamlines the pre‑commit review process and reduces the friction of auditing machine‑written code. The result is a faster, more reliable workflow that keeps human oversight sharp.