JSON validator
Check whether your JSON is valid, and if it isn’t, see exactly where and why: the line, the column and a plain explanation. Runs in your browser.
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How it works
- 1
Paste or open your JSON
It is checked as you type, so you can fix it in place.
- 2
Read the result
Valid JSON shows a summary of its structure. Invalid JSON shows the first error, with the line highlighted.
- 3
Jump to the error
Go to error puts the cursor right where the problem is. Common causes: trailing commas, single quotes, unquoted keys.
Questions
- Why is my JSON invalid?
- The usual suspects are a comma after the last item, keys or strings in single quotes, unquoted keys, comments, or a missing closing bracket. JSON is stricter than JavaScript.
- Which JSON standard is used?
- Strict JSON (RFC 8259), the same rules as JSON.parse in every browser.
- Does it catch duplicate keys?
- Yes. Duplicate keys are technically allowed, so the JSON still counts as valid, but you get a warning with the line and column, because most parsers silently keep only the last value.
- Is my JSON sent anywhere?
- No. Validation happens in this tab; nothing is uploaded.