JSON Diff Viewer

Highlights added, removed, and changed fields. Good for configs and API responses.

Array diffs are compacted (no null padding). Example: [1,2,3] vs [1,2,3,4] => [4].

Live Diff summary

Left JSONPaste baseline payload

Right JSONPaste comparison payload

Missing in leftOnly on right

Nothing missing from left.

Missing in rightOnly on left

Nothing missing from right.

Diff summary

Differences will appear here.

Validates both sides Live as you type Fits desktop & mobile

How it works

Parses both JSON inputs, flattens keys, and compares values to show what is added, removed, or unchanged. Arrays are compacted so indexes stay tight without null placeholders.

Diff summary lists counts plus a sample of keys for quick scanning.
Both sides must be valid JSON; malformed input is flagged next to its field.

Quick examples

Missing on right

Left: {"beta":false,"region":"us"}

Right: {"beta":false}

Only on left -> region

Only on right

Left: {"name":"StackAtlas","flags":{"beta":false}}

Right: {"name":"StackAtlas","flags":{"beta":false,"labs":true}}

Only on right -> flags.labs

Load the sample, then tweak a field to see added and removed keys update live.

Mini FAQ

Why no inline diff?

This tool highlights structural differences; for text diffs use the text diff tool.

Arrays look reordered?

Array indexes stay numeric; compacting removes gaps but keeps order.

Can I compare objects with different roots?

Yes, keys are flattened, so even nested differences surface in summaries and panels.

Related tools

JSON formatter Text diff CSV to JSON