How do I compare two documents for differences?

Paste both versions into a text diff tool. Added content shows in green, removed content in red. Lazyblink Text Diff Checker also shows a similarity percentage and works entirely in your browser.

Can I compare code files?

Yes — text diff works for any text including code, configuration files, and scripts. The monospace font and line numbers make code differences clear.

Is my text uploaded when comparing?

No — Lazyblink compares text entirely in your browser. Your content, including confidential contracts or code, never leaves your device.

How to Compare Two Texts and Find the Differences

Why Compare Texts?

Comparing two versions of text is a surprisingly common need. You have an original document and an edited version, and you need to see exactly what changed. Or you are reviewing a contract where a clause may have been quietly altered. Or you are checking whether two pieces of code differ.

A text diff tool highlights every addition, deletion, and change between two texts — far faster and more reliable than reading both side by side manually.

Common Use Cases

Contract review: Compare the version you agreed to against the version sent for signature. Spot any clauses that were changed, added, or removed.

Document revisions: See exactly what an editor or collaborator changed in your document.

Code comparison: Compare two versions of a code file, configuration, or script to identify what changed between them.

Content editing: Track changes between drafts of an article, essay, or report.

Plagiarism spot-checks: Compare two documents to see how similar they are.

Translation verification: Compare an original and a corrected translation.

How Text Comparison Works

Professional diff tools use the LCS (Longest Common Subsequence) algorithm — the same technology behind Git version control. It identifies the longest sequence of unchanged lines, then marks everything else as either added or removed.

The result shows:

Green lines: Text present in the new version but not the original (additions)

Red lines: Text present in the original but not the new version (deletions)

Unchanged lines: Text identical in both

Using Lazyblink Text Diff Checker

Paste your original text in the left box

Paste the changed text in the right box

Differences highlight instantly

See a similarity percentage score

Use "ignore case" and "ignore whitespace" for flexible comparison

Comparison Options Explained

Ignore case: Treats "Hello" and "hello" as identical. Useful when capitalisation changes are not meaningful.

Ignore whitespace: Treats different spacing and indentation as identical. Useful for code and formatted text where whitespace changes are cosmetic.

Privacy

The text comparison happens entirely in your browser. Your text — which may include confidential contracts or proprietary code — is never uploaded to any server.