EveryToolText Diff Checker - Compare Two Texts & Code Online Free
Compare two versions of any text, code, or document side by side and instantly see every addition, deletion, and change - highlighted line by line and word by word. Powered by the Myers diff algorithm - the same engine used in Git. Unlike Diffchecker.com and similar tools, EveryTool processes everything entirely in your browser: your text is never transmitted to any server, making it safe for source code, configs, legal documents, and API responses. Free, no signup, no limits.
100% Free & 100% Private
All processing happens entirely in your browser. We never upload your data to any server. No signup, no account, no hidden fees. Just free, secure tools.
How to Compare Two Texts Online
- Paste your original text in the left panel (Version A) and your modified text in the right panel (Version B).
- The diff computes instantly - deleted lines are highlighted red, added lines green.
- Word-level highlights within changed lines show exactly which words differ.
- Check the Stats Bar - lines added, removed, modified, and the overall similarity percentage.
- Switch between Side by Side, Unified, and Inline views.
- Use Change Navigation (← →) to jump between change blocks instantly.
- Enable JSON mode in Comparison Options for cleaner JSON comparison.
- Export as a .txt unified diff or styled HTML report.
Understanding the Three Diff Views
Side by Side View
The classic layout for reviewing code changes. Version A (original) on the left, Version B (modified) on the right. Both panels scroll simultaneously, keeping unchanged blocks aligned with spacer lines. Best for code reviews, config file comparisons, and any diff where seeing both versions at once reduces cognitive load.
Unified View
All changes combined in a single column, in sequential order. Deleted lines marked with minus (-) in red, inserted lines with plus (+) in green. Consecutive unchanged lines are collapsed to reduce noise. Best for copying, sharing, or generating patch output - this is the standard format used by Git and GNU diff.
Inline View
A focused view showing only the changed sections. Each change block displays the before (red) and after (green) lines together, with all unchanged sections fully collapsed. Ideal for rapidly scanning edits in large documents without scrolling through unchanged content.
What is the Myers Diff Algorithm?
The Myers diff algorithm, created by Eugene Myers in 1986, is the algorithm that powers Git, GNU diff, and virtually every modern diff tool. It finds the shortest edit script - the minimum number of insertions and deletions required to transform one text into another.
This produces the most natural, human-readable diff because it minimizes unnecessary changes. When you run git diff or diff -u file1 file2, you are seeing Myers algorithm output. EveryTool implements the full Myers algorithm entirely in your browser - no server, no dependencies, no data transmitted.
Common Use Cases
Code Review & Refactoring
Compare source code before and after a refactor. See every changed line and variable - same algorithm as Git.
Document Revision Review
Track exactly what a collaborator changed in a shared document. Works with any plain-text export from Word or Google Docs.
Config File Auditing
Compare configuration files between environments (dev vs staging vs prod). Never miss a changed setting.
API Response Comparison
Spot unexpected changes between two API responses. Use JSON mode to normalize formatting before comparing.
Data Export Comparison
Identify what changed between two versions of a CSV, JSON export, or log file without manual scanning.
Proofreading & Editing
See exactly which words changed between drafts. Export the HTML report to share edit history with clients.
Test Output Verification
Compare expected vs actual test output. Instantly spot which assertion values changed between runs.
Formatter / Linter Check
Verify that a formatter or linter only changed whitespace and not actual code content.
EveryTool vs Diffchecker.com vs TextCompare.com
The critical difference is where your text is processed.
| Feature | EveryToolThis site | Diffchecker.com | TextCompare.com |
|---|---|---|---|
| Text processing location | Your browser | Their servers | Their servers |
| Text transmitted over network | Never | Yes (encrypted) | Yes |
| Word-level highlighting | ✓ | ✓ (Pro only) | ✗ |
| JSON normalization mode | ✓ | ✓ (Pro only) | ✗ |
| Similarity percentage | ✓ | ✓ | ✓ |
| HTML report export | ✓ | ✓ (Pro only) | ✗ |
| Merge tool (accept A/B) | ✓ | ✓ (Pro only) | ✗ |
| Account required | Never | For saves | No |
| 100% free, no limits | ✓ | Free tier limited | ✓ |
Based on publicly available information as of April 2026.
Keyboard Shortcuts
| Shortcut | Action |
|---|---|
→ Right Arrow | Jump to next change block |
← Left Arrow | Jump to previous change block |
Ctrl + A | Select all text in focused panel |
Ctrl + Z | Undo last edit in focused panel |
Tab | Move focus between interface controls |
Key Features
Same algorithm as Git and GNU diff - finds the shortest, most natural edit script.
Three layouts for different workflows. Switch instantly without re-computing.
Secondary diff within changed lines shows exactly which words differ, not just which lines.
Live count of lines added, removed, modified, and the overall similarity percentage.
Normalizes JSON formatting before diffing - eliminates false differences from indentation.
Filter out noise from whitespace, tab, or casing differences to focus on content.
Minimap sidebar shows change density - click to jump to any region instantly.
Accept individual changes from Version A or Version B to build a merged result.
Download a self-contained, color-highlighted HTML diff report sharable in any browser.
Everything runs in your browser. No text is ever transmitted to any server.
No file size cap, no daily usage limits, no account required, no watermarks.
Share small diffs via a generated URL - recipients see the same diff without signup.
Frequently Asked Questions
How do I compare two texts online?
Paste your original text in the left panel (Version A) and your modified text in the right panel (Version B). The diff is computed instantly using the Myers algorithm - no button press needed. Deleted lines are highlighted red, added lines are highlighted green, and word-level highlights show exactly which individual words changed within each line. Use the change navigation arrows to jump between differences and the stats bar to see added, removed, and modified counts.
Can this tool compare JSON files?
Yes. Enable JSON mode in the Comparison Options panel. The tool normalizes both inputs by pretty-printing them with consistent formatting before computing the diff. This eliminates false differences caused by indentation, spacing, or key ordering, so you see only meaningful content changes rather than formatting noise. JSON mode is particularly useful for comparing API responses, configuration files, and data exports where formatting may differ between environments.
What is the Myers diff algorithm?
The Myers diff algorithm, published by Eugene Myers in 1986, is the standard algorithm used in Git, GNU diff, and virtually every modern diff tool. It finds the shortest edit script - the minimum number of insertions and deletions required to transform one text into another. This produces the most natural, human-readable diff output because it minimizes unnecessary changes. EveryTool implements the full Myers algorithm natively in the browser without any external libraries or server calls.
Can I ignore whitespace when comparing?
Yes. Open the Comparison Options panel and enable 'Ignore whitespace changes'. This normalizes leading and trailing spaces, tabs, and internal whitespace differences so that only meaningful content changes are highlighted. You can also enable ignore-case comparison, which makes the diff case-insensitive, and normalize line endings to handle differences between Windows (CRLF), Unix (LF), and Mac (CR) line endings - useful when comparing files edited across different operating systems.
Can I export the diff result?
Yes. Two export formats are available. Download as a plain-text unified diff file (.txt) - this is the standard diff format compatible with patch tools and version control systems. Download as a styled HTML report - a self-contained HTML file with full color highlighting, statistics, and formatting that works in any browser without any external dependencies. You can also copy the unified diff to clipboard directly from the interface for pasting into code reviews, ticket systems, or emails.
What is word-level diff highlighting?
Within lines that have changed, the tool runs a secondary diff pass on individual words to show precisely which words were added, removed, or modified - not just which lines changed. Deleted words within a changed line are highlighted in darker red and inserted words in darker green. This is particularly useful for spotting single-word changes in long lines of code, configuration values, or prose, where a line-level diff alone would force you to manually scan for the changed word.
How is the similarity percentage calculated?
Similarity is calculated using the Sørensen-Dice coefficient: (2 × matching characters) ÷ (total characters in A + total characters in B) × 100. Two identical texts score 100%. Completely different texts with no common sequences score 0%. The percentage reflects character-level similarity, not semantic meaning - two texts that discuss the same topic in different words will score low. The metric is useful for quickly gauging how much a document has changed between versions.
Is this text diff tool free?
Yes, completely free with no account or signup required, no usage limits, and no watermarks on exported results. All diff computation happens entirely in your browser using a native Myers diff implementation. No text is ever sent to any server. There are no daily caps, no file size restrictions beyond your device's available memory, and no premium tier. You can compare texts of any length, export results, and use all features at no cost.
Is my text safe when I paste it into an online diff checker?
On EveryTool, yes - completely. All diff processing runs entirely in your browser using JavaScript. Your text never leaves your device and is never transmitted to any server. This is fundamentally different from tools like Diffchecker.com and text-compare.com which send your text to their servers for comparison (even if they claim to delete it afterward). EveryTool's browser-based architecture makes it safe to compare source code, configuration files, legal documents, API keys, and any sensitive content without any privacy risk.
What is the unified diff format?
The unified diff format is the standard output format produced by GNU diff with the -u flag and used by Git for patches. It combines both versions of a file into a single stream: lines beginning with '-' are removed, lines beginning with '+' are added, and lines beginning with ' ' (space) are unchanged context. Context lines (typically 3 lines of unchanged text above and below each change block) help locate changes in the original file. The @@ markers indicate the line positions in each file. This format is compatible with the 'patch' command and most version control systems.
How is EveryTool's diff checker different from Diffchecker.com?
The key difference is privacy. Diffchecker.com processes your text on their servers - your content is transmitted over the network even if they claim to delete it afterward. EveryTool processes everything in your browser; your text never leaves your device. EveryTool also adds word-level highlighting within changed lines, live similarity percentage, a merge tool to accept individual changes from A or B, JSON normalization mode, and HTML report export - features not available in Diffchecker's free tier.
How do I compare two Word documents online?
To compare Word documents using this tool: open each document in Microsoft Word or Google Docs, select all text (Ctrl+A), copy it (Ctrl+C), and paste it into the respective panel. The diff will highlight every changed line and word. For best results, paste as plain text to avoid formatting characters. If you need to compare the formatting markup itself rather than content, export both documents as plain text (.txt) files first, then paste the file contents.
What is git diff and how does it relate to this tool?
'git diff' is Git's built-in command for showing differences between commits, branches, files, or the working tree. It uses the Myers diff algorithm - the same algorithm this tool implements. When you run 'git diff', the output is in unified diff format with +/- line markers and @@ headers. EveryTool's diff checker lets you visualize the same information with color highlighting, word-level precision, and side-by-side layout - useful for reviewing large git diffs without a code editor or terminal.
Can I compare config files and code online?
Yes. The tool works with any plain-text content - source code, JSON, YAML, TOML, INI, XML, CSS, SQL, shell scripts, Dockerfiles, Nginx configs, or any other text-based format. Paste the two versions and the diff instantly shows every change. Enable JSON mode for JSON files to normalize formatting first. The tool handles large files efficiently since all processing is done locally on your device rather than being sent to a server with upload size limits.
What are the keyboard shortcuts for the diff checker?
The text diff checker supports keyboard shortcuts for navigating changes: press the right arrow key (→) to jump to the next change block, and the left arrow key (←) to go back to the previous change block. These shortcuts work when the diff result is in focus. You can also use Tab to move between interface controls. The change navigation shortcuts are particularly useful for reviewing large documents with many scattered differences without having to scroll manually.
What does it mean when the diff shows 'NaN' in line numbers?
NaN (Not a Number) in line numbers in the diff view indicates lines that were inserted in Version B and do not have a corresponding line number in Version A, or vice versa. This is a display artifact of the diff rendering when a line was added (it has no original line number) or deleted (it has no modified line number). It is a known rendering edge case in some diff views. The content of the line is still correctly identified as added or removed - the NaN only affects the line number display, not the actual diff result.
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