How do I compare two text files online?

Paste your two texts into the left and right panels of the FixTools Diff Checker and click Compare. All differences are highlighted immediately — no software or sign-up required.

Does FixTools support file upload for comparison?

Yes. You can paste text directly or upload plain text files (.txt) into either panel. The diff runs in your browser on the file contents.

Are my files uploaded to a server?

No. All diffing happens client-side in your browser using JavaScript. Your text content is never sent to FixTools servers.

What types of files can I compare?

Any plain text content works: source code, configuration files, logs, markdown, HTML, CSS, JSON, XML, and more.

Can I compare files larger than a few kilobytes?

Yes. The browser-based diff handles files limited only by your device memory, which is typically several hundred megabytes on modern machines.

Browse tools

Free · Fast · Privacy-first

Compare Two Text Files Online

Paste or upload two text files and see every difference highlighted instantly. FixTools Diff Checker runs entirely in your browser — your content is never sent to a server. Spot additions, deletions, and modifications at a glance.

⚡ Use Tool Now How it works

Cost: Free forever
Sign-up: Not required
Processing: In your browser
Privacy: Files stay local

⚡

Side-by-side and inline diff views

🔒

Highlights additions, deletions, and changes

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Supports plain text, code, and markup

Developer Tool

Diff Checker

All processing happens in your browser — your files are never uploaded to any server.

🚀Open Diff Checker

100% Free · No account · Works on any device

How to use this tool

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Paste your original text in the left panel and your updated text in the right panel, then click Compare to see all differences highlighted.

How It Works

Step-by-step guide to compare two text files online:

1
Open the Diff Checker
Click "Open Diff Checker" to launch the tool in your browser.
2
Paste your original text
Paste or type your original (baseline) text into the left panel.
3
Paste your updated text
Paste or type the new version of the text into the right panel.
4
Click Compare
Click the Compare button to run the diff. Additions appear in green, deletions in red, and unchanged lines remain unformatted.
5
Review the differences
Scroll through the results to review every change. Switch between side-by-side and inline views as needed.