JSON Validator
Find out in one keystroke whether your JSON is valid — and exactly where it breaks if not. The validator reports the precise error position, then pretty-prints anything that passes.
How it works
Paste your document into the box. A green verdict confirms validity with a key/item count; a red verdict quotes the parser error including line and column. The Pretty-print button formats valid documents.
Formula and source
Validation parses against the JSON grammar (ECMA-404) and surfaces the parser's first error with its character position. Source: json.org (ECMA-404), https://www.json.org — last verified 2026-10-09.
Worked examples
- {"name":"Ava","age":30,"tags":["x","y"]} ? Valid — 3 keys reported
- {"a":1,} (trailing comma) ? Invalid — error flagged at the comma position
Common mistakes
- Confusing "valid JSON" with "correct data" — a validator checks syntax, not whether fields are right.
- Forgetting that numbers like 01 or .5 are illegal in strict JSON.
- Pasting JavaScript object literals (unquoted keys, functions) and expecting them to pass.
Tips
- Fix the FIRST reported error — later ones are often knock-on effects.
- After validating, use the JSON Path Extractor to pull out nested values.