Compare two texts and find differences instantly. Highlights additions, deletions, and changes. Perfect for code review, document comparison, content updates, and version control.
Reviewing code before commit? Paste old and new versions to see exactly what changed. Highlights additions/deletions line-by-line. Perfect for pull request reviews, debugging, or understanding teammate's changes.
Compare contract versions, terms of service updates, or policy changes. See what clauses were added/removed. Essential for legal review, content audits, or understanding what changed between document versions.
Two similar texts but can't spot the difference? Our tool highlights every character change. Use for proofreading, detecting plagiarism, comparing translations, or finding subtle typos in large documents.
Comparing README files, documentation, or blog posts in Markdown? See which headings, links, or code blocks changed. Perfect for GitHub README updates or technical writing revisions.
Changed .env, nginx.conf, or package.json? Compare before/after to verify you didn't break anything. Spot which environment variables, dependencies, or settings were modified.
Translator updated your content? Compare original and revised translations to see what phrases were changed. Useful for localization QA, translation review, or understanding editor's corrections.
Comparing two texts sounds trivial but is a classic computer-science problem. Diff tools compute the longest common subsequence (LCS) — the longest run of lines (or words) that appear in both versions in the same order. Everything outside that common backbone is then marked as added or removed. This is the same family of algorithms behind git diff, Microsoft Word's "Compare Documents" feature, and the review view in GitHub pull requests.
Line-level diffs are fast and ideal for code and structured text. Word- or character-level diffs are better for prose, where a single reworded phrase would otherwise flag the whole paragraph as changed. When reviewing legal or editorial edits, focus on the word-level highlights inside changed lines — that's where the substantive changes hide.
Contract and document review. When a counterparty returns "the same document with a few small changes", never take that on faith. Paste both versions and see every altered clause in seconds — including changes nobody mentioned.
Code review without git. Comparing two config files, two SQL queries, or a snippet before and after refactoring, when the files aren't in version control. Perfect for spotting the one changed line in a 500-line configuration.
Editing and coursework. Writers compare drafts to see an editor's changes; teachers compare submissions to spot copied passages; translators verify that a revision didn't silently drop a paragraph.
Debugging data problems. Two API responses, two log excerpts, two CSV exports that "should be identical" — a diff finds the discrepancy far faster than eyeballing. For structured JSON, pretty-print both sides with the JSON Formatter first so the diff aligns cleanly line by line.
No. The comparison runs entirely in your browser with JavaScript. That makes this tool safe for confidential material like contracts and unreleased copy — nothing is transmitted, logged, or stored.
Yes — paste any plain text, including source code. The diff is whitespace-sensitive, so indentation changes are detected too, which matters for languages like Python and formats like YAML.
The tool comfortably handles documents of tens of thousands of lines. Extremely large files (many megabytes) may slow the browser down, since the comparison work grows with the product of the two document lengths.
Usually invisible characters: trailing spaces, tabs vs. spaces, or Windows (CRLF) vs. Unix (LF) line endings. Non-breaking spaces pasted from Word are another classic culprit. These are real differences in the underlying text even though the lines render identically on screen.
This tool shows differences; merging is manual. Review the highlights, then copy the lines you want into your master version. For three-way merges of source code, a version control system like git is the right tool for the job.