Integration Lab JSON Tools

JSON Validator

Check JSON against the standard and see exactly where it breaks — the line, the column and a plain-English reason.

Input

Empty Ln 1, Col 1 0 B

Output

Nothing to format yet

Paste JSON into the input, drop a .json file onto it, or pull one in from a URL.

Waiting for input $

How to use the JSON Validator

Paste your JSON, open a .json file, or load it from a URL.
The status turns green for valid JSON, or the error panel shows the line, column and what went wrong.
Press Go to error to jump straight to the problem, fix it, and the check runs again as you type.

Questions

Which mistakes does it catch?

Everything the JSON standard (RFC 8259) forbids: trailing commas, single-quoted strings, unquoted keys, comments, missing commas or brackets, leading zeros, Python's True/None, and line breaks inside strings.

Are duplicate keys an error?

No — the standard allows them, so they are accepted. The Tree view shows both entries so you can spot and remove the duplicate.

Why does my JSON work in JavaScript but fail here?

JavaScript object literals allow things JSON does not, such as single quotes, unquoted keys and trailing commas. APIs and webhooks expect strict JSON.