About the Text Diff Checker
Overview
The Text Diff Checker compares two text inputs and highlights what was added or removed. Additions are shown in green; deletions in red with strikethrough. The comparison is word-based so you can see exactly which words changed between the original and modified versions. Use it to compare drafts, spot edits, or verify content changes. For comparing full documents or articles for similarity (e.g. duplicate content), use the Duplicate Content Checker. For JSON or code, the JSON Formatter and version control diff tools may also be useful.
When to use it
Use the diff checker when you have two versions of a document (e.g. before and after edit, original and translation) and want to see exactly what changed. It helps with proofreading, contract comparison, and content updates. For similarity between multiple articles or duplicate detection use the Duplicate Content Checker. For formatting or validating JSON use the JSON Formatter. The tool does not store your text; it runs in your session.
How to use it
Paste the original text in the left area and the modified text in the right area. Click Compare. The result shows the merged diff with additions highlighted in green and deletions in red with strikethrough. Scroll to review all changes. Use Clear to reset both inputs and the result. The comparison is done in the browser or in a single request; we do not store or log the content. For very long texts, consider splitting into smaller chunks if the tool becomes slow.
Tips
Ensure both texts are in the same encoding (e.g. UTF-8) to avoid spurious differences. Trim leading or trailing whitespace if you care only about content changes. For code or structured text, line-based diff tools might be more appropriate. To check whether two articles are too similar (SEO or plagiarism concern), use the Duplicate Content Checker which uses shingle-based similarity. The Keyword Density Analyzer helps with content analysis on a single text.
Common mistakes
Pasting the same text in both boxes will show no differences. Swapping original and modified will flip the colors (additions become deletions and vice versa). Very large inputs may slow the browser; there is no hard limit but keep inputs reasonable. This tool is for plain text comparison; for binary files or images use dedicated diff or comparison software. For duplicate or similarity checks across many documents use the Duplicate Content Checker, not this tool.