Generate, render, and apply code diffs.

Alto Code Diff compares text, renders structured differences, and parses, emits, or applies unified patches. It works with strings: reading and writing files remains the responsibility of your application.

Introduction

Diffing

  • Comparison covers options, word-level changes, limits, and the result model.
  • Rendering produces unified text, HTML, JSON, or ANSI output.
  • Engines explains the built-in algorithms and extension points.

Patches

  • Patches parses, emits, and applies single-file or multi-file unified patches.

The package rejects binary input and does not read files, execute Git, or resolve patch conflicts automatically.