Validate JSON syntax
Check whether text is supported, syntactically valid JSON.
Local processing · Nothing is uploaded · 1 MB input limit
Input & settings
Ready. Enter your input to begin.
How to use this tool
Paste the JSON document to validate. Success returns a machine-readable valid flag; malformed input produces a specific error.
Limits and behavior
This checks syntax, not a business schema. Numbers outside the safe integer range are rejected. Input is limited to 1 MB and output to 3 MB. No input content is saved by CraftAI.
Check whether JSON text is well formed
Use this free JSON validator to verify that pasted objects, arrays and values follow JSON syntax. This helps diagnose missing commas, incorrect quotes or unmatched brackets.
Does valid JSON guarantee the expected data structure?
No. Syntactic validity only confirms that JSON can be parsed; applications may also require particular fields and types.
Related tools: JSON formatter · Validate against JSON Schema