--- title: "Diff Checker" description: "Compare two texts side by side and find the differences. Highlight additions, deletions, and changes with our online diff tool." url: https://findutils.com/text/diff-checker/ category: text --- # Diff Checker Compare two texts side by side and find the differences. Highlight additions, deletions, and changes with our online diff tool. **Use this tool:** [Diff Checker](https://findutils.com/text/diff-checker/) ## Programmatic access - REST id `text-diff`: POST https://api.findutils.com/api/tools/text-diff/execute (reference: https://findutils.com/api/text-diff/) - MCP tool `text_diff` on https://mcp.findutils.com (reference: https://findutils.com/mcp/text-diff/) ## Why use a Diff Checker? A diff checker is an essential tool for comparing two versions of text to identify what has changed. Whether you're reviewing code changes, comparing document revisions, checking contract modifications, or verifying content updates, our diff tool makes it easy to spot every addition, deletion, and modification. The color-coded highlighting ensures you never miss a change, while the flexible comparison modes (characters, words, or lines) let you analyze changes at the granularity you need. ## Tips for Better Comparisons - Use line comparison mode for code and character mode for catching typos in prose. - Enable Ignore Whitespace when comparing code that may have different indentation styles. - Enable Ignore Case to focus on content changes rather than capitalization differences. - Upload files directly instead of pasting to preserve exact formatting and line endings. - Use the Swap button to quickly reverse which text is treated as original and which as modified. ## Frequently Asked Questions ### How does the diff checker work? Our diff checker uses the Longest Common Subsequence (LCS) algorithm to compare two texts and identify the differences. It breaks down the text into segments based on your chosen comparison mode (characters, words, or lines), then highlights what was added, removed, or kept the same. Green highlighting shows additions, red shows deletions, and unmarked text remains unchanged. ### What's the difference between character, word, and line comparison? Character comparison analyzes every single character, making it ideal for spotting typos or minor edits. Word comparison treats each word as a unit, perfect for document revisions and content changes. Line comparison is best for code reviews and structured documents where changes typically happen line by line. Choose based on what level of detail you need. ### Can I compare files directly? Yes! You can upload text files (.txt.md.json.xml.html.css.js.ts) directly using the upload button above each text area. The file content will be loaded automatically for comparison. This is especially useful for comparing code files or configuration files. ### What do 'Ignore case' and 'Ignore whitespace' options do? The 'Ignore case' option treats uppercase and lowercase letters as identical, so 'Hello' and 'hello' would be considered the same. 'Ignore whitespace' normalizes all whitespace (spaces, tabs, multiple spaces) to single spaces, useful when formatting changes but content remains the same. These options help you focus on meaningful differences. ### Is my text data secure? Yes, absolutely! All text comparison happens entirely in your browser using JavaScript. Your text is never uploaded to any server, making it completely private and secure. You can use this tool with sensitive documents, code, or confidential content without any privacy concerns. ### What file types can I compare? You can compare any text-based file including.txt.md.json.xml.html.css.js.ts.yaml.csv, and more. The upload button accepts these formats directly. Binary files like images, PDFs, or executables are not supported since the tool works with plain text content. ### Does the diff checker require a signup? No. The FindUtils Diff Checker is available with no signup, no usage limits. You can compare as many texts as you need without creating an account or paying for a subscription. ### Can I use this for comparing code? Absolutely. The line comparison mode is designed for code reviews and works similarly to how Git and GitHub display diffs. You can upload source files directly, and the side-by-side view makes it easy to review changes across functions, classes, or entire modules. ### What is the maximum text length supported? Since all processing happens in your browser, the practical limit depends on your device's memory. Most modern browsers handle comparisons of several hundred thousand characters without issues. For very large files exceeding a few megabytes, you may experience slower performance on older devices. ### How is this different from the JSON Comparer tool? The Diff Checker works with any plain text content and compares it character by character, word by word, or line by line. The JSON Comparer is specifically designed for JSON data and understands the structure of objects, arrays, and nested keys. If you are comparing JSON files, the JSON Comparer gives you a more meaningful, structure-aware diff. ### Can I compare two CSV exports here? You can, but a line diff is the wrong tool when the rows are in a different order: every moved row shows as removed and added. For spreadsheets exported from a CRM, shop or database, use [CSV Diff](https://findutils.com/convert/csv-diff/), which matches rows by a key column and lists only the rows that were added, removed or actually changed. ## Related Tools - [CSV Diff](https://findutils.com/convert/csv-diff/) - [Word Counter](https://findutils.com/text/word-counter/) - [Case Converter](https://findutils.com/text/case-converter/) - [Text Summarizer](https://findutils.com/text/text-summarizer/) - [Character Counter](https://findutils.com/text/character-counter/) - [JSON Comparer](https://findutils.com/developers/json-comparer/) - [JSON Diff](https://findutils.com/developers/json-diff/) - [HTML Formatter](https://findutils.com/developers/html-formatter/)