JSON
JSON Validator
Validate JSON syntax against RFC 8259 in real time. Precise line and column error reporting, 100% client-side.
JSON Validator
Paste JSON, drop a file, or
Why use our JSON Validator?
100% private
Everything runs in your browser. Your data never leaves your device — safe for production payloads.
Instant results
No round trips, no rate limits, no login. Format, validate and inspect megabytes of JSON in milliseconds.
Standards-first
Follows RFC 8259 / ECMA-404 exactly. Reports errors with precise line and column diagnostics.
Related developer tools
JSON Schema Validator
Validate JSON documents against a JSON Schema (draft-07 / 2019-09 / 2020-12) with precise error paths.
OpenXML Validator
Validate XML syntax with detailed error messages. Instantly find missing tags, unquoted attributes and malformed structure.
OpenJSON Compare
Side-by-side comparison of two JSON documents with structural highlighting to spot differences instantly.
OpenJSON Diff
Structural diff of two JSON objects or arrays showing added, removed and modified keys with paths.
OpenJSON Minifier
Strip whitespace and shrink JSON payloads to the smallest possible size for APIs, storage, and network transfer.
OpenJSON Parser
Parse JSON strings into structured objects with instant syntax errors, a live tree view and copyable JSON paths.
OpenRelated reading
Deep-dive guides that pair well with the JSON Validator.
Developer Tips
10 common JSON errors and how to fix them
Every JSON syntax error you'll ever see — trailing commas, unquoted keys, bad escapes — with a working repair strategy.
ReadTutorials
The complete JSON validation guide
How to validate JSON at every layer — parser, JSON Schema, and business logic — with practical examples.
ReadComparisons
JSON Formatter vs JSON Validator: what's the difference?
Formatters make JSON readable. Validators prove it is correct. Here's when to reach for each — and why great tools do both.
Read