JSON Validator
Check that your JSON is well-formed and pinpoint the first error.
Opens the editor with the sample loaded. Validation runs live in your browser as you type — nothing is uploaded.
A JSON validator answers one question fast: is this text valid JSON, and if not, where does it break? JSON Wallet validates as you type. Paste or drop a document into the editor and a live Valid / Invalid badge appears instantly. When the parser rejects the input, it reports the exact line and column of the first error so you can jump straight to it instead of scanning hundreds of lines by eye.
What the validator checks
Validation follows the strict JSON grammar (RFC 8259), the same rules JSON.parse() and every server-side parser enforce. That means it flags the mistakes that actually stop code from parsing:
- Trailing commas after the last item in an object or array
- Single quotes instead of double quotes around keys and strings
- Unquoted keys copied from JavaScript object literals
- Missing or mismatched brackets and braces
- Python-style
True,FalseandNone - Unescaped control characters, such as a raw newline inside a string
Validate, then fix in the same place
Finding the error is only half the job. Once the badge shows what is wrong, switch the same document to tree view to see which branch fails to render, or run Repair to strip trailing commas, convert single quotes and balance brackets automatically. You never leave the page or re-paste the data.
Private by design
Most online validators POST your JSON to a server to check it. JSON Wallet does not. The entire validator runs as client-side code in your browser, so API responses containing tokens, internal configuration or customer records are safe to paste here. Nothing is sent anywhere, logged or stored.
Frequently asked questions
How do I validate JSON online for free?
Paste your JSON into the editor above. A live Valid / Invalid badge appears immediately, and when the JSON is invalid it shows the exact line and column of the first error. It is free and requires no signup.
Is my JSON uploaded to a server to validate it?
No. Validation runs entirely in your browser using the same rules as JSON.parse(). Your data never leaves your device.
What is the difference between validating and repairing JSON?
Validating tells you whether the JSON is well-formed and where it breaks. Repairing rewrites common mistakes — trailing commas, single quotes, unquoted keys — into valid JSON. You can do both here.
Related tools
Prefer to start from scratch? Open the JSON editor and paste your own data — everything runs locally in your browser.