JSON Validator
The JSON validator parses a document and either confirms it is valid or reports the precise line, column and character where parsing failed, along with a summary of the structure — how many keys, arrays and levels of nesting it contains.
JSON to validate
Validation result
Your result will appear here.
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Results update automatically and are calculated on your device. Nothing you type is sent to a server.
Runs in your browser. Processing happens entirely in your browser. Nothing you enter is sent to Delimiter.live.
How to use the JSON Validator
- Paste the JSON you want to check.
- A green result means the document parses; a red one names the line, column and offending character.
- Fix the reported position and validate again — errors are reported one at a time, starting with the first.
Example
Input
{"a":1,}
Output
Invalid JSON Line 1, column 8: unexpected '}' — JSON does not allow a trailing comma.
Common use cases
- Diagnosing why an API rejected a request body.
- Checking a configuration file after a hand edit.
- Confirming that a generated payload is well-formed before sending it.
Limitations and things to watch for
- This checks syntax, not meaning. A document can be perfectly valid JSON and still be rejected by an API for having the wrong fields; validating against a JSON Schema is a separate task.
- Only the first syntax error is reported, because a parser cannot reliably continue past one.
Frequently asked questions
What is the difference between validating and formatting?
Validating only answers whether the document parses and, if not, where it fails. Formatting also rewrites it with indentation. The JSON formatter reports the same errors, so use whichever fits your task.
Does it validate against a schema?
No. It checks JSON syntax only. Schema validation — confirming that required fields exist and have the right types — is a different operation and is not offered here.
Why does it say a trailing comma is invalid?
Because the JSON specification forbids it, even though JavaScript object literals allow it. Most strict parsers, including those in APIs, will reject the document.