Diff Checker

Compare two texts side-by-side and highlight added, removed, and changed lines.

Original
Modified

What is a Diff Checker?

A Diff Checker compares two pieces of text or code and highlights the differences between them. It is an essential tool for code review, debugging, and document comparison — showing exactly which lines were added, removed, or left unchanged.

+Added

Lines present in the right/new version only.

-Removed

Lines present in the left/original version only.

Unchanged

Lines identical in both versions.

Key Features

✓Line-by-line diff — See exactly which lines changed between the two versions
✓Color-coded output — Green for additions, red for removals, neutral for unchanged
✓Line number display — Both left and right line numbers shown for context
✓Statistics summary — Quick overview of how many lines were added, removed, or unchanged
✓Real-time comparison — Results update as you type in either panel
✓100% client-side — No data is ever sent to a server — safe for sensitive code

Common Use Cases

Code Review

Compare code versions to identify what changed before and after a patch or refactor.

Debugging

Find unintended changes between a working version and a broken version of a file.

Document Comparison

Spot differences between two versions of configuration files, README files, or documentation.

Configuration Drift

Detect differences between production and development config files.

Paste & Compare

Quickly compare clipboard content against a reference without opening a terminal.

Content Verification

Verify that two copies of data are identical or understand where they diverge.

Benefits for Developers

  • →Instant visibility: See exactly what changed between two texts without reading line by line.
  • →Reduces review time: Color-coded output lets you focus only on changed lines, not the entire file.
  • →No git required: Compare arbitrary text without needing a version control system.
  • →Handles any content: Works with source code, JSON, YAML, plain text, and any other text format.
  • →Private by design: Client-side only — your code and configuration data never leaves your machine.
  • →Zero setup: Runs instantly in any browser with no installation or sign-up.

Frequently Asked Questions

What is a diff checker?

A diff checker compares two pieces of text and shows the differences between them. It highlights added lines in green, removed lines in red, and unchanged lines neutrally.

What is line-by-line diff?

Line-by-line diff compares the two inputs one line at a time and marks each line as added, removed, or unchanged. This is the standard format used by tools like git diff.

Can I compare code?

Yes. The tool works with any text including source code, JSON, YAML, HTML, Markdown, and configuration files. Syntax is not parsed — only the raw text is compared.

Is this tool safe to use?

Yes. All comparison happens in your browser using JavaScript. No data is sent to any server, making it safe to compare sensitive code or configuration.

Is this tool free?

Yes. The Diff Checker on NexoraTools is completely free with no sign-up or restrictions.