JSON Validator
FreeValidate JSON syntax and structure with detailed errors
About JSON Validator
A misplaced comma or an unclosed bracket can break an entire config load, API call, or build step, and the cryptic error your runtime throws rarely points to the exact spot. The JSON Validator from ToolHub by Codaiman checks your JSON the moment you paste it, confirming the syntax is correct and the structure is well formed before it ever reaches your code.
Paste any JSON, from a single object to a deeply nested payload, and the tool parses it and flags problems with clear, line-aware error messages so you can jump straight to the fix. It runs entirely in your browser, needs no signup, and returns results instantly, so sensitive keys and tokens in your data never leave your machine. Free to use as often as you like.
Common uses
- Checking an API response or webhook payload before writing parsing logic against it
- Validating package.json, tsconfig.json, or another config file after a manual edit
- Pinpointing the exact line of a syntax error your application's JSON parser only reports vaguely
- Confirming a JSON string copied from logs or a database column is intact and parseable
- Teaching or reviewing JSON structure when onboarding to a new data format
How to use
- 1
Configure options
Set your preferences using the options panel below.
- 2
Click Generate
Click the process button to generate your result instantly.
- 3
Copy or download
Copy the result to clipboard or download it directly to your device.
Why ToolHub?
- Instant error detection
- Detailed error messages
- Standards compliant
FAQ
Does it validate against a schema?
No. This tool checks syntax and structural validity only. To check data against a JSON Schema definition, use the dedicated Schema Validator.
Is my JSON data uploaded anywhere?
No. Validation runs in your browser, so your data never leaves your device. It is safe to paste payloads that contain tokens or personal data.
Will it tell me where the error is?
Yes. When parsing fails, you get a clear error message indicating the problem and its location so you can correct it quickly.
Can it handle large JSON files?
Yes, it handles sizable payloads well. Extremely large files may depend on your browser's available memory.
Can I use JSON Validator on mobile?
Yes — ToolHub is fully responsive and works on iPhone, Android, tablets and all modern browsers. No app install needed.