Tools
Compare two blocks of text or code side-by-side or unified, with word/char highlighting and a downloadable patch.
Compare two texts or files with live line-by-line diffing, word or character level highlighting on changed lines, a JSON mode that ignores key order, and a downloadable unified diff. Runs entirely in your browser using a hand-written Myers diff. Nothing is uploaded.
Diff Checker shows exactly what changed between two versions of a text. Paste the original on the left and the new version on the right, and every added, removed and edited line is marked, with the changed words or characters highlighted inside each line. It works for source code, config files, JSON, logs and plain prose, and the result can be copied or downloaded as a standard unified diff.
A hand-written Myers diff recomputes as you type, debounced so it never lags behind.
Compare in two aligned columns on desktop, or a single unified view with old/new gutters. Unified on mobile.
Pretty-prints both sides with recursively sorted keys before diffing, so key order and formatting never count as a change.
Diffing runs in a background worker with a 3-second timeout, so a huge paste never locks the tab.
Runs of more than 8 unchanged lines collapse to 3 lines of context, with a click to expand.
Both texts stay in your browser. Nothing is uploaded, and nothing is saved to this device either.
Paste the older version into the Original box, drop a file onto it, or use the upload button.
Put the newer version in the Changed box. The comparison runs automatically as you type.
Tick Ignore whitespace, Ignore case, Ignore blank lines or Trim trailing whitespace, or switch on JSON mode for JSON data.
Switch between side-by-side and unified views, highlight by word or character, and press [ or ] to jump between changes.
Copy the output as a unified diff or download a .diff file to apply with git apply or patch.
Both texts stay in your browser. The diff is computed by a Web Worker on your own device and nothing is sent to a server. The text itself is never saved; only your view settings, such as layout and ignore options, are remembered in local storage.
Free online tool to format, beautify, and validate JSON. Features include syntax highlighting, minification, error detection, and customizable indentation. No signup required, 100% private - all processing happens in your browser.
Test regular expressions against your own text with live match highlighting, per-match capture groups and a token-by-token explain panel. Switch to replace mode to preview substitutions, or load a ready-made pattern from the library. Everything runs in your browser so nothing is uploaded.
Convert text between UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case and more. Perfect for developers, writers, and anyone who needs to quickly change text case.
Developed by MadMVP
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