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FAQ — Diff Checker
Diff Checker — frequently asked questions
What is a diff checker?
A diff checker (also called a text compare tool, diff tool, or text diff) compares two blocks of text or code and highlights the differences between them. It shows which lines were added, removed, or changed — making it essential for code reviews, document comparisons, and content editing.
Is this diff checker completely free?
Yes, 100% free with no limits. Unlike Diffchecker.com which charges $9/month for syntax highlighting and file uploads, this tool gives you everything — character-level diffs, split and unified views, file uploads, ignore whitespace — all free, no signup, no paywall, no ads.
Is my data safe and private?
Yes. This diff checker runs entirely in your browser using JavaScript. No text is ever sent to a server. Your code and documents stay on your machine. You can verify this in your browser's network tab.
What is the difference between split and unified view?
Split view shows original text on the left and modified text on the right, aligned line by line — ideal for side-by-side comparison. Unified view shows both versions in a single column with + and - prefixes, similar to git diff output — great for reviewing changes sequentially.
What are character-level diffs?
When a line is changed (not purely added or removed), character-level diffs highlight the exact characters that differ within that line. For example, if you change color: red to color: blue, only red and blue are highlighted — not the entire line.
Can I compare files from my computer?
Yes. Click the Load file button on either side to select a file. Any text file, code file, config file, log file, CSV, or JSON file works. Files are read entirely in your browser.
What does "Ignore whitespace" do?
It ignores differences in spaces, tabs, and indentation. This is useful when comparing code that has been reformatted or when you only care about content changes, not formatting.
Can I share a diff with someone?
Click Copy diff to copy the unified diff to your clipboard in standard diff format, ready to paste into Slack, email, or a pull request. You can also click Download .diff to save it as a file.
What keyboard shortcuts are available?
Ctrl+Enter (or Cmd+Enter on Mac) runs the diff. Tab in the text areas inserts a tab character for code editing.
How does this compare to Diffchecker.com or Meld?
Diffchecker.com paywalls syntax highlighting, file uploads, and diff history behind a $9/month subscription. Meld is a desktop app requiring installation. This tool provides all core features free in your browser — no install, no account, no limits.
Free Online Diff Checker — Compare Text & Code
This free diff checker lets you compare any two blocks of text, code, or data instantly. Designed as a free alternative to paid diff tools like Diffchecker Pro ($9/month), this tool runs 100% in your browser with zero server-side processing.
Features included free (no paywall)
Side-by-side (split) and unified diff views, character-level difference highlighting, ignore whitespace and case options, file uploads from your computer, line numbers, context-only mode, copy and download diffs in standard format, and keyboard shortcuts. All features work without signup, without limits, and without ads.
Use cases
Compare code changes before committing, review document edits, diff configuration files across environments, compare API responses, check contract revisions, verify database migrations, and validate translation files. Works with any plain text format including JavaScript, Python, HTML, CSS, JSON, YAML, XML, SQL, Markdown, and more.
Privacy-first design
Unlike cloud-based diff tools, your text never leaves your browser. This is especially important when comparing sensitive code, contracts, credentials, or proprietary data. Zero network requests with your content — verify in DevTools.