Text Diff Checker
Last updated: June 13, 2026Compare two texts line by line.
Text Diff Checker is a free online tool to compare two texts line by line. It runs entirely in your browser, so your files never leave your device — nothing is uploaded. There's no sign-up, no watermark, and it works on any modern browser on desktop or mobile.
How to use Text Diff Checker
The Text Diff Checker compares two blocks of text and highlights exactly what was added and removed, line by line. It's great for comparing code, contracts, drafts and config. Runs entirely in your browser — nothing is uploaded.
Read the full guide: How to Compare Two Texts: Diff Checker (Free)
- 1Paste the original text on the left.
- 2Paste the changed text on the right.
- 3Read the highlighted line-by-line differences.
Clear line diff
Added lines in green, removed in red, with a summary count.
Any text
Compare code, documents, lists or config side by side.
Private
Both texts stay on your device — nothing is uploaded.
Compare two contract versions
When a counterparty returns a revised agreement, paste the original on the left and their version on the right to see every altered clause at a glance. The line-by-line highlighting surfaces a quietly changed payment term, deleted liability sentence, or added paragraph that a quick read would miss, so you can review edits with confidence before signing or sending it to legal.
Spot what changed in config files
Paste a working .env, JSON, or YAML config beside a broken one to instantly find the line that drifted between environments. Because the diff is line-based and monospaced, a flipped flag, mistyped port, or missing key stands out in red or green, helping you debug a deployment that suddenly stopped working without scanning both files manually.
Check two drafts for edits
Dropped an old draft next to a freshly edited one and need to know exactly what moved? Paste both blocks to see added sentences in green and removed ones in red, with a running count. It is ideal for confirming a proofreader's changes, reviewing an AI rewrite against your original, or tracking revisions when you are not using version control.
Text Diff Checker — frequently asked questions
How does it compare the text?
It uses a longest-common-subsequence diff on the lines, so it finds the minimal set of additions and removals between the two versions.
Can I compare code?
Yes — it's line-based and monospaced, which works well for code, JSON and config files.
Is my text uploaded?
No — the comparison runs entirely in your browser.
Is it free?
Yes, completely free.
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