Compare Two Text Files Online

Free online tool to compare two text files and merge differences. No sign-up, 100% private — runs in your browser.

How to Compare Two Text Files Online

Open two files — click "Open File" in the left and right panes, or simply paste text into each editor.
Diff Suite instantly highlights every difference: added lines in green, removed lines in red, side by side.
Use the merge arrows to move changes between the two files, then copy the merged result.

The comparison runs entirely in your browser. Your files are never uploaded, which makes this tool safe for source code, contracts, and other sensitive content.

Why Compare Two Text Files?

Code review — spot exactly which lines changed between two versions of a script.
Document drafts — see revisions in contracts, specs, or articles before accepting them.
Config files — diff JSON, YAML, INI, or environment files before deploying.
Log analysis — find new error lines between two log captures.
Translation work — compare source and translated text line by line.
Data cleaning — spot added or removed rows in CSV exports.

Features

Real-time diff — recomputed on every keystroke.
Visual merge arrows — pull changes left or right with one click.
Open local files — supports .txt, .md, .csv, .json, .xml, .yml, .html, .js, .py, .log and more.
Edit menu — sort lines, remove duplicates, trim whitespace, replace line breaks.
Undo and redo per pane, switch texts, clear all.
100% private — no upload, no sign-up, no tracking.

Frequently Asked Questions

How do I compare two text files online?

Open this page, click "Open File" in the left pane and select your first file, then do the same in the right pane for the second file. Differences appear instantly. You can also paste text directly into either editor.

Can I compare 2 text files without uploading them?

Yes. Diff Suite reads your files locally in the browser. The content never leaves your device, so it is safe for source code, contracts, and API keys.

Is there a program to compare two text files that runs in the browser?

Yes — Diff Suite is exactly that. It is a browser-based alternative to desktop software like WinMerge. No installation, no admin rights, works on macOS, Linux, ChromeOS, and Windows.

What file formats can I compare?

Any plain-text format: .txt, .md, .csv, .json, .xml, .yml, .html, .js, .py, .log, and more. If it is text, Diff Suite can compare it.

Can I merge the two files after comparing?

Yes. Use the red and green merge arrows to move changes between the left and right panes, then copy the result. The Plus version adds copy buttons for each pane.

Is this free?

Yes, 100% free with no sign-up and no usage limits.

Compare Two Text Files vs. Other Methods

Method	Install needed	Cross-platform	Private	Cost
Diff Suite (this page)	No	Yes (any browser)	Yes (runs locally)	Free
Desktop software (WinMerge, Beyond Compare)	Yes	Windows only (mostly)	Yes	Free or paid
Command-line `diff`	Yes	Yes	Yes	Free
Online tools that upload files	No	Yes	No	Free or paid

Related Tools

Text Compare & Merge Online — the main Diff Suite tool page.
WinMerge Online Alternative — run a WinMerge-style diff in your browser.
Mergely Alternative — a ready-to-use merge tool vs. the Mergely library.
Text Compare Plus — same tool plus find/replace and copy buttons.