Diff Checker is a small Android utility built around one job: drop in two versions of the same text and see exactly what changed between them. That is a task that comes up everywhere, not just on a phone, so we built a browser version of the same idea. Paste your original text on one side and the edited version on the other, and the differences light up as you type, line by line and word by word, with a running count of what got added and what got removed.
Compare text now
Edit either box below and the diff updates as you type. Turn on “Ignore whitespace” or “Ignore case” if you only care about the substance of the change.
How to use it
Two sample paragraphs load by default so you can see the highlighting before you type a single character. Replace either one with your own text, or paste over both. The diff panel below recomputes on every keystroke: removed lines get a red background with a “-” marker, added lines get a green background with a “+” marker, and when a line was edited rather than replaced outright, the changed words themselves are underlined or struck through so you can see exactly which part moved.
The two toggles change what counts as a difference without changing your text. “Ignore whitespace” treats extra spaces, tabs, and line-wrapping as identical, useful when comparing code that got reformatted. “Ignore case” treats “Report” and “report” as the same word, useful when comparing copy that only changed in capitalization. Use “Swap” to flip which side is the original, and “Clear” to start over. Your last input is saved on your device between visits, and nothing you paste is ever sent anywhere; the comparison happens entirely in your browser.
How it compares to Diff Checker
This page keeps the part of the Android app people use most: paste two versions of a text and immediately see what changed, highlighted at both the line and word level, with no “compare” button to press first. That live-diff feel, edit and watch the highlighting move, is the whole loop, and we kept the ignore-whitespace and ignore-case options because they are what turn a noisy diff into a useful one.
The full Diff Checker app goes further. It supports comparing entire files rather than pasted blocks, keeps a history of past comparisons you can return to later, and works fully offline as an installed app with no browser tab to keep open. It is built for people who diff text often enough that a dedicated app earns a spot on their home screen.
We left out file import, history, and offline installation on purpose. Those are native-app conveniences for someone who compares text daily. This page is for the smaller, more frequent moment: you have two paragraphs, two drafts, or two snippets of code right now, and you need to see what changed in the next few seconds, on whatever device you happen to be using. For a quick check, this is faster than opening an app. For a daily workflow with a history of past comparisons, install Diff Checker.
Get the full app
Diff Checker is free on Android, with file comparison, saved comparison history, and full offline use for people who compare text regularly.
Frequently asked questions
Can I compare text online for free?
Yes. This page compares text entirely in your browser, for free, with no signup, no download, and no limit on how many times you use it.
Is my text uploaded anywhere?
No. The comparison runs entirely client-side in your browser. Nothing you paste ever leaves your device or reaches a server; there is no upload step to worry about.
Does it work with code, not just plain text?
Yes. Paste source code, config files, or any plain text into either box. Turn on “Ignore whitespace” to skip over reformatting and reindentation and focus on the lines that actually changed.
Does it work offline?
Yes. Once the page has loaded, comparing text keeps working without a connection. Your last input is saved in your browser’s local storage on your device only.
Is this the official Diff Checker app?
No. This is an original tool we built, inspired by the quick paste-and-compare job that Diff Checker does well. It is not affiliated with, endorsed by, or connected to its developer. For file comparison, saved history, and offline installation, get the official app above.
