Text Diff Checker
Paste two versions of a text, config or JSON document and see exactly which lines were added, removed or changed.
Runs in your browser — nothing is uploaded.
Ignores formatting and key order.
How to use it
- Paste the original on the left and the changed version on the right. The comparison updates as you type.
- Switch between side-by-side and inline views. Green lines were added, red lines were removed.
- Tick “Ignore whitespace” or “Ignore case” to hide noise. Tick “JSON mode” to compare two JSON documents regardless of formatting and key order.
- Use “Swap sides” to reverse the comparison.
Frequently asked questions
Is my text uploaded?
No. The comparison runs in your browser and nothing is sent anywhere. Large inputs are processed in a background worker.
Does it compare words or characters?
It compares whole lines. A line that differs in any way is shown as removed on the left and added on the right, paired on the same row.
What does JSON mode do?
Both sides are parsed and printed again with sorted keys and the same indentation before comparing, so only real differences in the data remain. If either side is not valid JSON the error says which one.
What are the limits?
Up to 5 million characters per side. At most 20,000 rows are displayed, although the counts cover everything. When two big texts have almost nothing in common, the differing middle is shown as entirely replaced instead of searching for a finer match.
Are line endings an issue?
No. Windows (CRLF) and Unix (LF) line endings are treated as equal, and so is a missing final newline.