Diff Checker — Text & JSON

Compare two texts side-by-side with highlighted differences. Supports plain text and smart JSON-aware diffing.

Free Always No Account Needed 100% Client-Side
Mode:+4 added-3 removed
Diff Output
  {-   "name": "John Doe",-   "age": 30,-   "email": "john@example.com"+   "name": "Jane Doe",+   "age": 31,+   "email": "jane@example.com",+   "role": "admin"  }

About this tool

The Diff Checker shows the exact differences between two pieces of text, highlighting additions in green and deletions in red — the same visual format used by GitHub and git.

Plain text mode compares line-by-line and character-by-character, showing exactly what changed between two versions of a document, config file, or code snippet.

JSON-aware mode is smarter: it parses both inputs as JSON, normalizes formatting (removing whitespace differences), and then diffs the result. This means you'll only see semantic changes — an added key or changed value — not formatting noise.

Use it to compare API responses, config files, code versions, database dumps, or any two texts. The diff is computed using the Myers diff algorithm for optimal, minimal edits.

Frequently Asked Questions

What algorithm is used for diffing?
The Myers diff algorithm, which produces the minimal edit script between two texts. This is the same algorithm used by git.
What is JSON-aware diffing?
JSON-aware mode normalizes both JSONs before comparing, so formatting differences (extra spaces, different key order) don't appear as changes.
Can I diff large files?
Yes, but very large texts (>100KB) may be slower. The diff runs entirely in your browser.
How do I read the diff colors?
Green background = added in the right text. Red background = removed from the left text. Gray = unchanged.

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