Text diff checker
Paste two versions of a text, config file or code snippet to see exactly which lines were added, removed or changed.
🔒 Runs entirely in your browser. Nothing you paste is uploaded or sent to a server.
How the diff works
The tool uses the Myers diff algorithm, the same one git diff uses by default. It finds the smallest set of added and removed lines that turns the original into the changed text. A line that was edited shows up as one removal plus one addition; in the side-by-side view such pairs are shown on the same row, with the changed characters highlighted.
- Side by side is easiest to read for config files and short documents.
- Unified is the format of
diff -uandgit diff:-lines are removed,+lines are added, and@@ -12,7 +12,8 @@headers give the starting line and length of each hunk in the old and new file. Copy as patch gives you text thatpatchorgit applycan use.
Ignore options
Ignore whitespace treats lines as equal when they differ only in spaces or tabs (indentation, trailing spaces, several spaces in a row), similar to git diff -w. Use it to review a re-indented file without noise. Ignore case compares lines case-insensitively, useful for SQL and HTML.
If every line shows as changed although the texts look identical, the cause is almost always invisible: different line endings (CRLF vs LF), a byte order mark, tabs vs spaces or trailing whitespace. Tick Ignore whitespace to confirm, then check the file with the line ending & whitespace inspector.
Command-line equivalents
| Task | Command |
|---|---|
| Compare two files | diff -u old.txt new.txt |
| Ignore whitespace | diff -uw old.txt new.txt or git diff -w |
| Word-level changes | git diff --word-diff |
| Two files outside a repo | git diff --no-index a.txt b.txt |
| Apply a patch | patch -p0 < change.diff or git apply change.diff |
Both texts stay in your browser. Nothing is uploaded, so you can safely compare private configs, logs and code.
Last updated 2026-11-05.