Developer tool
Text Diff Checker
Compare two texts side by side or inline at line or word level, highlight additions and removals, and ignore whitespace or case, all in your browser.
Free, no sign-up. Runs in your browser; nothing is uploaded.
Original
Changed
Options
Differences
How to use the text diff checker
Spot exactly what changed
Paste an original text on the left and a changed version on the right. The tool finds the smallest set of edits that turns one into the other and highlights them. Use it to review a copy edit, compare two config files, check a contract revision or see what a teammate changed in a draft.
Pick a view
- Side by side shows both versions in two columns. Removed lines are red on the left, added lines are green on the right, and lines that were edited sit on the same row with the exact changed words marked inside them.
- Inline shows one column with removals and additions in sequence, like a patch.
Pick a level
- Line compares whole lines. It is the right choice for code, logs, CSV rows and lists.
- Word compares word by word and punctuation by punctuation. It is the right choice for sentences and paragraphs, where a single changed word should not flag the whole line.
Options that reduce noise
- Ignore whitespace treats runs of spaces and tabs as equal and ignores indentation, so reformatting does not drown the real changes.
- Ignore case treats Apple and apple as the same.
- Swap exchanges the two boxes so you can see the change from the other direction.
Reading the result
The counters show how many items were added and removed, and a clear "Identical" message appears when nothing differs under your chosen options. If two texts look the same but are reported different, switch on ignore whitespace; invisible differences such as trailing spaces, tabs and different line endings are the usual cause.
Tips
- Compare small sections for the clearest result; a diff of two unrelated documents is mostly noise.
- For code reviews, keep line level on and ignore whitespace off, because indentation matters in many languages.
- Your text stays in your browser. Nothing is sent to a server.
Frequently asked questions
What is the difference between line and word level?
Line level marks whole lines as added or removed, which suits code and lists. Word level marks only the words that changed inside a sentence, which suits prose and copy edits.
What does ignore whitespace do?
Runs of spaces and tabs are treated as one space and leading or trailing spaces are ignored, so a reindented line is not reported as a change.
How does side by side work?
Lines are compared first. When a removed line is followed by an added line they are shown on the same row and the changed words inside them are highlighted.
How big a text can I compare?
Thousands of lines work smoothly. Very large inputs fall back to a coarser comparison to keep the page responsive.
Can I compare files?
Paste the contents of each file into the boxes. Your text is never uploaded.
Which algorithm is used?
A longest-common-subsequence diff, the same idea behind git diff, which finds the smallest set of additions and removals.