The standards behind JSON document
Which specs JSON Formatter validates against, in plain English. Browser-based, free, no signup, runs entirely on your device.
JSON Formatter is one of those tools you reach for once a day without thinking about it. Paste a JSON document, find out if it's valid, copy the cleaned-up version back. Thirty seconds.
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Which specs JSON Formatter validates against
JSON Formatter validates against the published spec for the JSON document format, with the official errata applied. Where the spec is ambiguous, JSON Formatter sides with whichever interpretation the major parsers (in the relevant language ecosystems) follow.
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Frequently asked questions
Will JSON Formatter fix the JSON document for me?
JSON Formatter suggests fixes for the most common errors. You decide whether to apply each one.
Does JSON Formatter support schema validation?
JSON Formatter catches syntactic errors. For schema (semantic) validation, pair JSON Formatter with a schema validator on top.
Does JSON Formatter upload my JSON document?
No. JSON Formatter validates entirely in your browser using WebAssembly. Nothing leaves your device.
Can I validate a really large JSON document?
Up to a few hundred MB works on a normal laptop. For larger, a CLI tool is the right shape.
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- Best practices when validating a JSON document (2026 edition)
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Last reviewed May 2026. File-size limits, portal requirements, and software defaults change over time — always verify with the destination platform before uploading time-sensitive documents. References to third-party services and products are for descriptive purposes only and do not imply any partnership or endorsement.