Diff Checker & Text Compare

Paste two versions of any text to instantly see every addition, deletion, and unchanged line — highlighted side by side.

Free
Original paste or type
Modified paste or type
or press Ctrl + Enter

Free Online Diff Checker — Compare Any Two Texts Instantly

Our diff checker lets you paste two versions of any text and immediately see exactly what changed. Whether you are comparing document revisions, code changes, contract edits, or any two blocks of text, the tool highlights additions in green and deletions in red so differences are impossible to miss — no sign-in required.

Two Display Modes: Split and Unified

  • Split view — shows the original text on the left and the modified text on the right, with corresponding lines aligned side by side. Changed lines are highlighted in each column so you can read both versions simultaneously and follow every edit in context.
  • Unified view — merges both versions into a single column with + and markers alongside each line, identical to a standard Git diff output. Useful when you want a compact summary of all changes in one scroll.

Lines Mode vs. Words Mode

Lines mode compares your text line by line — the standard approach for code, configuration files, and any structured content where line boundaries are meaningful. A line is classified as added, removed, or unchanged as a unit.

Words mode breaks the comparison down to individual words and highlights only the specific words that changed within each line. This is ideal for editing prose, blog posts, legal documents, or any content where small wording changes matter more than line-level structure.

Who Uses a Diff Checker?

  • Developers reviewing code changes, merge conflicts, or configuration diffs before deploying
  • Writers and editors tracking draft revisions and tracking changes between versions
  • Legal and compliance teams comparing contract or policy versions for precise wording changes
  • Students and academics proofreading essays and comparing submission drafts
  • Content teams auditing copy updates and A/B test variants
  • Data analysts comparing exported reports or CSV structures across time periods

Privacy — Everything Stays in Your Browser

The entire diff comparison is performed by JavaScript running locally in your browser tab. Your text is never transmitted to or stored on any server. You can disconnect from the internet after loading the page and the tool continues working perfectly. Zero logs. Zero tracking. Zero data retention — nothing leaves your device.

Frequently Asked Questions

What is a diff checker?
A diff checker compares two versions of text and highlights exactly what changed — which lines or words were added, removed, or left unchanged. It uses the same algorithm as version-control tools like Git to produce a clear, colour-coded view of every difference.
Is my text stored or sent anywhere?
No. The comparison runs entirely in your browser using JavaScript. Your text never leaves your device — no server receives it, no logs are kept, and nothing is retained after you close the tab.
What is the difference between Split view and Unified view?
Split view displays the original text on the left and the modified text on the right so you can read both at once, with matching lines aligned side by side. Unified view merges both versions into a single column and uses + and − markers — similar to a Git diff output. Split view is available in Lines mode only.
What is the difference between Lines mode and Words mode?
Lines mode compares whole lines, which is ideal for code, configuration files, and structured documents. Words mode breaks the comparison down to individual words so you can spot small inline edits without the entire line being flagged as changed — useful for prose and document editing.
Can I use this to compare source code?
Yes. Paste any plain text — source code, JSON, YAML, SQL, HTML, Markdown, or prose. For code, Lines mode works best since code is naturally organised by line. For documents where small wording matters, try Words mode.