↔️ Text Diff Checker
Paste two versions of a text and see additions and deletions highlighted line by line in a familiar diff format.
How to Use the Text Diff Checker
The Text Diff Checker compares two versions of a text and highlights exactly what changed, line by line. Paste the original version of your text into the Text A panel on the left, and the modified version into Text B on the right. Click Compare to see the differences highlighted below. Lines that only appear in Text A (deleted lines) are shown with a red background and a - prefix. Lines that only appear in Text B (added lines) are shown with a green background and a + prefix. Lines that are identical appear in grey with no prefix.
This tool performs a line-by-line comparison — it is ideal for comparing code, configuration files, documents, markdown files, legal texts, or any content where you need to see exactly what was added or removed between two versions. Common use cases include reviewing edits before committing code, comparing two versions of a document, checking what changed in a config file, or auditing content changes. Click Clear to reset both panels and start a new comparison.
Frequently Asked Questions
What is a text diff?
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A diff (short for "difference") is a representation of the changes between two versions of a text. The output marks which lines were added, which were deleted, and which stayed the same. The concept comes from the Unix diff command-line tool, which has been used by developers since 1974 to compare file versions and generate patches.
What do + and - mean in a diff?
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In a standard diff output, lines prefixed with + (shown in green) are lines that exist in the second (modified) version but not in the first (original). Lines prefixed with - (shown in red) are lines that exist in the first (original) version but not in the second. Lines with no prefix exist in both versions and are unchanged.
Can I use this to compare code files?
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Yes. The Text Diff Checker works for any text-based content, including source code, JSON, XML, HTML, CSS, configuration files, markdown, and plain text. For comparing large codebases or tracking changes over time, dedicated version control tools like Git are more powerful, but for quick one-off comparisons this tool is fast and convenient.
Does the diff checker compare word by word or line by line?
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This tool compares text line by line, which is the standard approach used by tools like Git diff, Unix diff, and code review systems. Each line in Text A is compared against the corresponding line in Text B. If lines differ, the entire old line is shown as deleted and the entire new line as added. Word-level inline diff highlighting is planned for a future update.