Text Diff Checker
Paste two versions of a text and see additions, deletions, and changes highlighted side-by-side. Useful for comparing configs, code snippets, and documents.
Why use a Text Diff tool?
Manually comparing two blocks of text is slow and error-prone — especially for long documents, config files, or code snippets. A diff tool automatically computes the minimal set of changes and highlights added and removed lines so you can review changes in seconds. It's invaluable for comparing error messages, reviewing copy edits, or auditing config changes. For structured data, try the JSON diff tool. Browse all tools in the developer tools category.
Line-level diff
Uses the longest common subsequence (LCS) algorithm to find the minimal edit distance between two texts.
Color highlighting
Added lines appear in green, removed lines in red, and unchanged lines in gray — matching the universal diff convention.
Change summary
A header shows the total count of added and removed lines so you can gauge the scale of changes at a glance.
Diff algorithm types & use cases
Different diff granularities are suited to different tasks. This tool uses line-level diffing, the most common approach.
| Algorithm type | Granularity | Best for |
|---|---|---|
| Line diff | One line at a time | Code reviews, config files, log comparisons (git diff default) |
| Word diff | One word at a time | Prose editing, documentation, minor config value changes |
| Character diff | One character at a time | Spotting typos, single-character encoding changes, DNA sequences |
| Semantic diff | Meaning / AST level | Code refactoring — ignores whitespace-only reformatting |