Compare Two Texts Online
Check the difference between two texts instantly. Side-by-side or unified highlighting, compare by line, word, or character, ignore whitespace or case, plus Semantic JSON for order-independent object diffs. 100% in your browser.
Online text diff: compare documents, code, and JSON in your browser
An online text diff checker answers a simple question: what changed between two versions of a file, message, or config? Instant Tools runs a Myers line diff in your browser, so drafts, contracts, logs, and source snippets never leave your device. Paste the original on the left and the revised version on the right, then compare. Split view keeps both sides aligned for side-by-side review; unified view produces a patch-style stream you can copy into tickets or pull requests.
Beyond basic line compare, choose word or character granularity when a single paragraph or token changed inside a long line. Toggle ignore whitespace or ignore case when formatting noise would drown real edits. For API payloads and config objects, Semantic JSON mode sorts keys and pretty-prints both sides first, so reordered properties do not look like content changes. Pair that with the JSON Formatter when you need validation before diffing. Agent and system-prompt authors can continue in Prompt Diff for rules-focused workflows with the same Myers engine. All of this stays free, with no signup and no upload to Instant Tools servers.
How this compares to other online diff tools
Many free diff sites only highlight line changes in one view, or upload your file to their server. Instant Tools keeps comparison local, offers split and unified layouts, and adds Semantic JSON when key order would otherwise look like a rewrite. Word and character modes help when a single line changed inside a paragraph. If you only need to format JSON before comparing, start on the JSON Formatter and return here with Semantic JSON enabled.
How to Use
- • Granularity: Line for files, word for paragraph edits, character for tiny token changes
- • Ignore whitespace / case: Hide formatting-only noise
- • Semantic JSON: Order-independent compare when both sides are valid JSON
- • Split View: Side-by-side columns with highlighted differences
- • Unified View: Single stream with +/- indicators
How to Use
- 1Paste your original text in the left field
- 2Paste the modified text in the right field
- 3Pick line, word, or character granularity (or enable Semantic JSON)
- 4Optionally ignore whitespace or case, then click Compare
- 5Switch between split and unified views and copy the output
Tips
- •Use split view for side-by-side comparison of large texts
- •Word mode highlights edits inside a long line without drowning in character noise
- •Semantic JSON ignores key order so reordered objects do not look changed
- •Perfect for code review, document comparison, and change tracking
Common Use Cases
Code Review
Compare before and after code changes to review modificationsDocument Changes
Track changes in contracts, policies, or legal documentsJSON Configs
Use Semantic JSON to compare API payloads without key-order noiseFrequently Asked Questions
How do I compare two texts online?
Paste the original text on the left and the modified text on the right, then click Compare. Additions and deletions are highlighted. Switch to unified view, or compare by word or character when you need finer detail.
What is a text diff checker?
A text diff checker compares two versions of text and highlights additions, deletions, and unchanged lines. Use it for code review, contract redlines, config changes, or any side-by-side comparison. Free and instant in your browser.
Does this use the same algorithm as Git?
Yes. This tool uses the Myers diff algorithm, the same line-diff engine behind Git, Mercurial, and many IDEs. Results match what you'd expect from git diff on plain text.
What's the difference between split and unified view?
Split view shows original and modified text in two columns with color highlights. Unified view merges both into one stream with +/- prefixes, like a patch file, ideal for copying into tickets or PRs.
What is Semantic JSON mode?
When both sides are valid JSON, Semantic JSON sorts object keys and pretty-prints before diffing. That way key order alone does not show up as a change. If either side fails to parse, you get a clear message instead of a misleading text diff.
Can I compare two text files online for free?
Yes. Paste both versions into the left and right panels and click Compare. There is no file upload to our servers. Everything runs in your browser, so drafts and code stay on your device.
How is side-by-side text compare different from a word processor track changes?
Track changes needs one document with revision marks. This tool compares any two plain texts, including code, logs, JSON, or pasted email threads. Split view aligns both sides; unified view outputs a patch you can paste into GitHub or Jira.
Is my text sent to a server?
No. Comparison runs entirely in your browser with JavaScript. Your documents never leave your device.