Text Diff Tool
Compare two blocks of text side by side — line-level and character-level differences highlighted. Great for proofreading and merge conflicts.
Last updated: April 2026 · Runs in your browser · No sign-up
Common use cases
Writers compare drafts before and after editing. Developers review config changes outside of git. Lawyers compare contract versions. Translators check what changed in source copy between rounds.
Reading a diff
- Green — added in the new version.
- Red — removed from the old version.
- Unchanged lines provide context so you can locate each change.
Frequently Asked Questions
What algorithm does the diff use?
A Myers-style longest-common-subsequence diff, the same family used by git. It finds the smallest set of insertions and deletions needed to transform one text into the other.
Does it handle very large files?
Myers diff is O(n·d); for inputs up to a few thousand lines it's instantaneous. Novel-length inputs may pause for a second but still work.
Is whitespace ignored?
By default, no — every character counts. Most diff tools offer a whitespace-insensitive mode for comparing code where indentation changes aren't meaningful.
Can it compare JSON or XML?
It does a textual diff, which works but isn't semantic. For structural diffs (re-ordered keys shouldn't count), use a dedicated JSON diff tool.