Diff Viewer

About

Diff Viewer is a developer-focused text comparison tool that
runs entirely inside your browser. Paste any two pieces of
text — source code, JSON, config files, prose, SQL, logs —
and instantly see exactly what changed.

No servers. No accounts. No telemetry.

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✦ CORE FEATURES
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▸ Side-by-Side & Inline diff views
  Switch between a two-column layout or a unified
  inline view at any time — even after comparing.

▸ Word-Level Diff Highlighting
  Toggle granular word-level highlighting inside
  changed lines so you can spot exactly which words
  were added, removed, or modified.

▸ Smart LCS Algorithm
  Uses an optimized Longest Common Subsequence (LCS)
  engine with integer line hashing for fast, accurate
  diffs on large files.

▸ JSON Formatter
  One-click pretty-print for both panels before
  comparing — perfect for minified API responses.

▸ Live Statistics
  See added, removed, changed, and unchanged line
  counts at a glance in the stats bar.

▸ Panel Resizer
  Drag the center handle to resize the input panels
  to any split ratio you prefer.

▸ Swap Panels
  Instantly flip original ↔ modified with one click.

▸ Copy to Clipboard
  Copy either panel's content independently with
  visual confirmation feedback.

▸ Session Persistence
  Your text is remembered across popup open/close
  cycles within the same browser session.

▸ Keyboard Shortcuts
  · Ctrl/Cmd + Enter  →  Compare
  · Escape             →  Clear
  · Tab (in textarea)  →  Insert real tab character
  · Arrow keys         →  Resize panels (keyboard)

▸ RTL Language Support
  Full right-to-left layout for Arabic, Hebrew,
  Farsi, and other RTL locales.

▸ Dark & Light Mode
  Automatically follows your system preference via
  prefers-color-scheme.

▸ Accessibility First
  ARIA roles, live regions, keyboard navigation,
  and focus management throughout.

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✦ PRIVACY — THE SHORT VERSION
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• Zero network requests — ever.
• No analytics, no crash reporting, no ads.
• Text you paste is NEVER sent anywhere.
• All processing happens locally in your browser.
• No permissions to read your tabs, history,
  browsing data, or any web page content.
Learn more in the extension's privacy policy.*

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✦ PERFECT FOR
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Developers comparing code snippets or config files
Comparing JSON API responses before & after a change
Reviewing contract or document revisions
Checking log file differences
Comparing SQL queries or database schemas
Any situation where you need a quick offline diff

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✦ TECHNICAL DETAILS
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• Manifest V3
• Content Security Policy: script-src 'self' only
• No external scripts, fonts, or CDN resources
• No background service worker
• No content scripts injected into web pages
• All code is self-contained and auditable

* Privacy policy subject to change at any time; any changes will be announced