Home AlveaHubsfree, no sign-up, works offline

Text Comparison Tool — Free & Offline, No Sign-up

Compare two versions of any text and instantly see every addition and deletion highlighted word by word. Works entirely offline — your text never leaves your browser and is never sent to any server. Free, no sign-up, no file size limit.

Added Removed

About this tool

This text comparison tool highlights exactly what was added and what was removed between two versions of any text, word by word. The comparison uses a longest common subsequence (LCS) algorithm and runs entirely in your browser with no internet connection required. It is suitable for comparing confidential documents, contracts, or any sensitive text because nothing is ever transmitted.

How to use

  1. Paste the original text into the left field and the modified text into the right field.
  2. Click Compare.
  3. Additions are highlighted in green and deletions in red with strikethrough, shown inline in context.

When to use this tool

  • Reviewing changes between two drafts of a document, email, or contract before sending.
  • Spotting what changed in a configuration file, script, or code snippet.
  • Comparing two versions of a translated text to find divergences.
  • Checking whether an AI-rewritten paragraph changed the meaning of the original.
  • Comparing confidential text offline, without uploading it to a third-party service.

Why use an offline text comparison tool?

Most online diff tools send your text to a server to process it. This tool runs the comparison algorithm entirely in your browser using JavaScript. Once the page has loaded, it works with no internet connection — making it a safe choice for comparing sensitive documents, internal drafts, legal text, or anything you would rather not upload to a third-party server.

Frequently asked questions

Does this tool work offline?

Yes. Once the page has loaded, all comparison runs locally in your browser with no internet connection required. It is safe to use with confidential or sensitive text.

Is my text sent to a server?

No. The comparison runs entirely in JavaScript in your browser. Nothing you paste is ever transmitted or stored.

Does this compare line by line or word by word?

Word by word. The tool tokenizes both texts into words and whitespace, then finds differences using a longest common subsequence algorithm for a granular, readable result.

What is the maximum text size?

There is no hard limit. Very long texts may take a few seconds to process, and a warning is shown for large inputs.

Can I use this for code comparison?

Yes, but it is not syntax-aware. It treats code as plain text. For small snippets it works well; for large files a dedicated code diff tool may be more appropriate.

Can I use this to compare confidential documents?

Yes. Because everything runs locally and nothing is transmitted, it is safe to use with confidential documents, contracts, or any sensitive text.

How are additions and deletions shown?

Additions are highlighted in green and deletions in red with strikethrough, shown inline so you can read the final text with changes in context.

Is this tool free?

Yes, completely free with no sign-up required and no usage limits.

Everything is compared locally in your browser — no text is ever sent to a server.