Does this show character-level differences?

Yes. Within changed lines, the exact characters that differ are highlighted in addition to line-level highlighting.

Can I compare code files?

Yes. Paste any text content — code, configuration, prose — and the diff highlights all changes.

Is there a size limit?

No hard limit. The tool processes text in your browser, so very large files may be slower depending on your device.

Best Free Online Text Diff Tool

Comparing two versions of a text document to find exactly what changed is a fundamental task in writing, development, and operations. devtoolkit.sh's Text Diff tool renders a side-by-side or unified diff of any two text inputs, highlighting added lines in green and removed lines in red, with character-level highlighting within changed lines to pinpoint the exact words or characters that differ. This works for prose (comparing draft versions of an article or document), code (reviewing a small change without a full IDE), configuration files (checking what changed between environments), and any other text. The tool handles large texts efficiently in your browser, requires no file uploads, and — unlike many diff tools — never stores your content. It's immediately useful for reviewing AI-generated edits, comparing contract versions, or auditing configuration changes. The character-level diff within changed lines is especially valuable for spotting subtle modifications: a changed number, a removed word, or a switched character that would be easy to miss in a line-by-line review.

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FAQ

Does this show character-level differences?: Yes. Within changed lines, the exact characters that differ are highlighted in addition to line-level highlighting.
Can I compare code files?: Yes. Paste any text content — code, configuration, prose — and the diff highlights all changes.
Is there a size limit?: No hard limit. The tool processes text in your browser, so very large files may be slower depending on your device.