About Diff Viewer (Side-by-Side)

View unified or side-by-side diffs with syntax highlighting. Part of the DevTools Surf developer suite. Browse more tools in the Text / String collection.

Use Cases

• Review code changes before committing to version control
• Compare configuration files across environments
• Visualize database migration script differences
• Share highlighted diffs in pull request documentation

Tips

• Toggle between unified and side-by-side diff views
• Use syntax highlighting to spot changes in code diffs
• Paste two text blocks to generate an inline comparison

Fun Facts

• The diff utility was first developed by Douglas McIlroy at Bell Labs in 1974 and shipped with the 5th Edition of Unix.
• The unified diff format (showing + and - lines with @@ markers) was introduced by Wayne Davison in 1990 and became the git default.
• Git's diff algorithm is based on Eugene Myers' 1986 paper 'An O(ND) Difference Algorithm,' which finds the shortest edit script.

FAQ

What diff format does it accept?

Two text blocks (paste both sides), or a unified diff patch (single-pane view of @@ ... @@ hunks). Side-by-side layout re-renders the pair; unified shows patch-style.

Does it highlight word-level changes?

Yes — within a changed line, individual word changes are highlighted. This makes typo fixes vs full rewrites easy to tell apart.

Can I diff non-text content?

Diff works on any text. For binary files, convert to a text representation first (hex dump, base64). For images, use an image diff tool — visual diffs differ from text diffs.

Is the diff algorithm the same as git's?

Conceptually yes — longest-common-subsequence (Myers algorithm). The highlighting heuristics may differ in edge cases but output matches git for most inputs.