How to use JSON Validator
- 1. Paste or open a file. The validator runs on every edit. Invalid documents show a red error under the input.
- 2. Read line and column. Fix the reported position — trailing commas and single quotes are the usual suspects.
- 3. Repair if needed. Click Repair to fix common JSON5-style mistakes, then validate again.
About this tool
“JSON validator online” is a different intent from “formatter”: people often have a broken config or API response and need to know why parse fails. This page emphasizes validation with actionable error locations.
Strict JSON rules
JSON requires double-quoted keys and strings, no trailing commas, no comments, and no undefined. JavaScript object literals are not JSON — that mismatch causes most validation failures.
Validation is not schema checking
This tool checks syntax only. A document can be valid JSON but wrong for your API. Use JSON Schema in your tests or the JSON to TypeScript tool for shape checks.
Code examples
JavaScript
const payload = JSON.parse(raw);
console.log(JSON.stringify(payload, null, 2));Python
import json
print(json.dumps(json.loads(raw), indent=2, sort_keys=True))Go
var buf bytes.Buffer
if err := json.Indent(&buf, []byte(raw), "", " "); err != nil {
log.Fatal(err)
}