Compare JSON
Find structural JSON differences with path filters and a readable before-and-after change report.
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JSON tools
Work with JSON as a structure, not as text.
Flatten JSON
Turn nested JSON into reversible path records that preserve empty containers and unusual keys.
JSON Lines converter
Convert JSON arrays to JSONL or NDJSON and back with an individual record preview and clear line errors.
Merge JSON
Combine JSON documents with live conflict previews, deep or shallow merging, and explicit array rules.
Sort JSON keys
Sort nested JSON object keys alphabetically with a live preview while keeping array order intact.
JSON tree viewer
Explore JSON branches, navigate escaped paths, and export precisely the value you select.
Unflatten JSON
Restore nested JSON from explicit path records and explore the reconstructed structure.
JSON validator
Check JSON syntax, inspect value types and nesting depth, and save a clear local validation report.
Validate syntax, format and sort keys, flatten and unflatten, merge with conflict previews, compare structurally, browse with a tree viewer, and convert to and from JSON Lines.
Parsing is local, numbers with unsafe precision are flagged, and no schema or URL is fetched.
Understanding and fixing JSON
The JSON validator checks strict syntax and flags numbers that would lose precision. The tree viewer lets you browse large documents branch by branch and export exactly the value you select. Sorting keys makes two documents with the same content textually identical, which makes diffs readable. JSON compare goes further and reports structural differences by path, ignoring key order and formatting.
Flatten and unflatten turn nested documents into reversible path records and back, which is useful for editing in spreadsheets or comparing line by line. Merge combines documents with a choice of deep or shallow merging and an explicit rule for arrays, previewing conflicts before you export.
Details that cause real bugs
JSON is simple, but its edge cases cause real outages. Integers above 9,007,199,254,740,991 lose precision in JavaScript and many other parsers, which is why APIs like Twitter's send large IDs as strings. Duplicate keys are technically allowed, but different parsers keep different values. Comments and trailing commas are valid in JavaScript and JSON5 but not in JSON. The tools here follow strict JSON and warn about these cases rather than silently changing your data.
For data pipelines, the JSON Lines converter turns an array into one record per line and back. That format is used by log processors, data warehouses, and machine-learning datasets because each record can be processed on its own.