Compare JSON files online

Plain text

Whitespace and invisible characters — zero-width spaces, BOMs and non-breaking spaces copied from web pages produce differences you cannot see the cause of.

Indent

Sort by field value

Comma-separate keys and add ASC/DESC per key (ascending by default). Dot-notation for nested keys (address.city). Each panel is sorted independently, using whatever it holds:
• JSON — object key, e.g. category ASC, amount DESC
• CSV/TSV — column name or number, e.g. price DESC
• NDJSON — record field, e.g. ts DESC
• Text — whitespace column number, e.g. 2 DESC
Leave it empty to sort by whole value / whole line.

Descending Unique Ignore case

Other

Collapse Highlight

Editor

Word Wrap

Wrap long lines to fit editor width

Synchronized Scrolling

Lock scroll between left and right panels

Auto CSV→JSON

Automatically convert CSV to JSON on paste/drop

Auto Format JSON

Automatically format JSON on paste/drop

Auto Sort Keys

Automatically sort JSON keys on paste/drop

Auto Fix JSON

Repair broken JSON on paste — trailing commas, single quotes, unquoted keys, comments, missing brackets, Python syntax. A repair is never silent: it always leaves a notice saying what changed, with Undo. Turn this off to paste exactly what you copied and repair on demand from the panel chip instead.

DIFF VIEW SETTINGS

Block Diff (JSON)

Align whole array items / object keys so added & removed blocks read cleanly. Falls back to text diff for non-JSON.

Read JSON inside strings

A string value that holds a JSON object or array — stringified JSON, or a Python dict like {'a': None} — is shown and compared as nested keys. Only values that parse are expanded; anything else stays text. Display only: saving, Copy and Export keep the original strings.

Highlight Changes

Show character-level diffs in chunks

Highlight style Lines: every changed line tinted, changed text darker (the original look). Values: only the changed value or key is marked; unchanged property names stay plain. Characters: only the changed characters. Outline: no fills; changed text is outlined and added/removed lines get an edge bar. Whole added or removed lines stay marked in every style.

Show Gutter Markers

Display markers next to changed lines

Collapse Unchanged

Fold long sections of identical lines

Fold changes over A block of differences at least this many lines long gets a ▾ in the gutter that folds it in both panels; click the summary row to show it again. Alt+click a ▾ (or Alt+[ / Alt+]) folds or shows every block. 0 turns this off.

Collapse folds large changes too

With Collapse on, blocks over the fold size start folded as well, so only the smaller differences stay open.

Orientation Revert Controls

DIFF ALGORITHM

Scan Limit Max characters to scan (higher = slower)

PERFORMANCE

⚡ Performance Mode

Auto-collapse unchanged sections for faster rendering

🔍 Viewport Diff Mode

Only compute diffs for visible area (best for very large files)

📊 Performance active:

Exclude from diff

Matches are treated as identical on both sides — the field collapses, isn't counted, and shows no red/green (e.g. created_on / updated_at columns). Use plain text for an exact match, or /regex/flags for a pattern — e.g. /_id$/i.

Match against

No patterns yet — matches will be diffed normally.

Show grayed-out style

Tint excluded matches with a subdued gray background. Off = fully neutral (still no red/green).

Numeric tolerance

Ignore tiny floating-point differences: two numbers count as equal when their difference is within the tolerance (e.g. 0.001 treats values matching to 3 decimal places as identical — no red/green, not counted).

Enable numeric tolerance

Treat near-equal numbers as the same value in the diff.

Tolerance Max ignored difference (must be > 0)

Files

Examples

Theme

Help

Source on GitHub Switch to v5 (legacy)

Tip: Alt+↑ / Alt+↓ jump between differences

Ready to compare JSON

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Empty

Fix JSON

Differences

Fields by number of items affected

Items — click to jump

Key comparison

CodeMirror 6 (Modern) | ← Version Selector | Switch to v5 (Legacy)