Everything you need to know about the Diff Checker tool.
What is a Diff Checker and who needs it? ▼
A Diff Checker highlights differences between two texts or code files. It's used by developers reviewing code changes, writers comparing document drafts, QA engineers verifying outputs, and SEO professionals auditing web copy — essentially anyone who needs to pinpoint exactly what changed between two versions of text.
Is my text stored or sent to any server? ▼
No. All comparison logic runs entirely in your browser using JavaScript. Nothing is ever uploaded, stored, or transmitted to any external server. Your data remains completely private.
What file types can I upload? ▼
You can upload any plain-text file: .txt, .csv, .json, .xml, .html, .css, .js, .ts, .py, .java, .cpp, .php, .md, .yaml, .log, and more. Binary files like .docx or .pdf are not supported since we extract raw text only.
What's the difference between Line, Word, and Inline modes? ▼
Line mode compares entire lines and is best for code or structured text. Word mode highlights changes at the word level for prose editing. Inline mode shows both original and modified versions in a single pane with additions and deletions marked within the same flow, similar to GitHub's unified diff view.
What does "Ignore Whitespace" mean? ▼
When enabled, the tool treats multiple spaces, tabs, and leading/trailing whitespace as equivalent. This is useful when comparing code that has been re-indented or documents where only formatting — not content — changed.
Can I save or share my comparison? ▼
You can save your comparison to your browser's local storage and retrieve it later. You can also export the result as a .txt file using the Export button, or use the Share button to copy the page URL with pre-filled parameters for instant sharing.