What does JSON mode change?

It parses and pretty-prints valid JSON before comparing lines, so indentation differences do not appear as changes. Object key order is not rearranged.

What happens if one side is invalid JSON?

The page shows a warning and compares both inputs as plain text instead.

Does the checker merge changes?

No. It is a line-by-line comparison view; it does not edit either input or create a merged document.

Text & JSON Diff Checker

LocalFree

Compare two blocks of text or JSON and see exactly what changed — added and removed lines highlighted. JSON is pretty-printed first so key order never trips you up.

JSON mode (normalize before comparing)

Original

Changed

Differences

Paste text into both sides to compare.

Runs in your browser; files and input stay on this device

About diffing

A diff shows the minimal set of line changes between two versions — what was added, removed, or left unchanged. It’s how code review, Git, and merge tools work under the hood. This checker computes the diff with a longest-common-subsequence algorithm entirely in your browser, and can pretty-print JSON first so formatting or key spacing doesn’t create false differences.

How to use Text & JSON Diff Checker

1Paste the original text on one side and the changed version on the other.
2Enable JSON mode when both inputs should be parsed and normalized before comparison.
3Review the added and removed lines in the difference output.

Frequently asked questions

What does JSON mode change?: It parses and pretty-prints valid JSON before comparing lines, so indentation differences do not appear as changes. Object key order is not rearranged.
What happens if one side is invalid JSON?: The page shows a warning and compares both inputs as plain text instead.
Does the checker merge changes?: No. It is a line-by-line comparison view; it does not edit either input or create a merged document.