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Compare two texts line-by-line with inline changes. Legacy alias of text-diff-visual; prefer text-diff-visual or string-comparison for similarity %. Input: two texts ≤10MB. Returns diff. 100% client-side.
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Compares two text inputs highlighting differences in side-by-side or unified view at word, line, or character granularity. Supports ignoring whitespace and case differences, file upload for both inputs, downloading the diff as a .patch file, and line numbering with added/removed/modified counts in a summary bar.
Comparing text versions is a fundamental development task that extends beyond version control. A standalone diff checker with configurable granularity and exportable patches handles arbitrary text comparison without committing.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
Software developers reviewing code changes, writers comparing document revisions, data engineers verifying transformations, QA engineers comparing API responses, and anyone tracking changes between file versions.
Paste original text into left panel and modified text into right panel — or upload files via drag-and-drop
Select granularity: 'Word' (default), 'Line', or 'Character'
Configure options: 'Ignore Whitespace', 'Ignore Case', 'Trim Lines'
Choose view mode: 'Side-by-Side' or 'Unified' (single view with inline changes)
Review summary bar — shows added, removed, and unchanged counts
Click 'Download Patch' for .patch file compatible with git apply, or 'Swap' to exchange inputs
Original: 'Hello World' | Changed: 'Hello Earth' | Word => Shows 'World' deleted, 'Earth' insertedOriginal: 'function add(a,b){return a+b}' | Changed: 'function add(a, b) { return a + b; }' | Ignore Whitespace ON => 'No differences'What algorithm is used?
Myers diff algorithm, the same algorithm used by Git.
Can I compare cross-OS files?
Yes, but enable 'Ignore Whitespace' for CRLF vs LF.
How to apply a .patch file?
'git apply <file>.patch' or 'patch -p0 < <file>.patch'.
Character limit?
~500,000 chars in line mode. Character-level diff has ~50,000 char limit.
Authoritative specifications, standards, and in-depth reading for Text Diff Checker.
Visual side-by-side diff for two texts with char-level highlights. Use as default diff tool; for similarity score use string-comparison, for JSON use json-diff. Input: two texts ≤10MB. Returns visual diff. 100% client-side.
Sort lines alphabetically and remove duplicates. Use when cleaning lists; for comparing two texts use text-diff-visual. Input: text lines ≤10MB. Returns sorted unique lines. 100% client-side.
Find and replace text with literal, regex, and case-insensitive modes. Shows replacement count.
Reverse text by characters (grapheme-safe for emoji), words, or lines.
Count words, characters, and sentences. Get reading time and Flesch score as you type.
Preview rendered Markdown without editing. Use for quick read-only preview; for editing use markdown-editor, for HTML output copy use markdown-to-html. Input: Markdown ≤10MB. Returns rendered HTML preview. 100% client-side.
Generate URL slugs from titles with lowercase rules. Use as default slug tool; slugify-string is a noindex alias. Input: text ≤10MB. Returns slug string. 100% client-side.
Obfuscate strings with masking and reversible transforms. Use when hiding PII in demos; for hashing use hash-generator. Input: text ≤10MB. Returns obfuscated text. 100% client-side.