JSON Validator & JSON Schema Checker

Q: How do I get the line number of a JSON syntax error?

Send the document as a string in `json`. When parsing fails, `parse_error` contains `position`, `line` and `column` when the parser reports them.

Q: Can I validate syntax without a schema?

Yes. Omit `schema`; the response then only says whether the JSON is valid, with a note that no schema was given.

Check JSON syntax with exact line and column of errors, and validate data against a JSON Schema (draft 4, 7, 2019-09 or 2020-12).

Result

Press “Run” to see the result.

Send the document to check in json, either as a JSON string (so syntax errors can be reported) or as an already-parsed value. If it is not valid JSON, the response has valid_json: false and a parse_error with the message, character position, line and column. A raw text/plain body is also accepted as json.

Add a schema (object or JSON string) to validate the data against a JSON Schema. The default dialect is 2020-12; set draft to 4, 7 or 2019-09 for older schemas. Each error has the instance path (e.g. /age), the failing keyword, the schema_path and a readable message; up to 200 errors are returned. Without a schema, only the syntax is checked.

The request body is limited to 5 MB. An invalid schema returns a 400 error with code invalid_schema.

Use this in your code

curl -X POST "https://apibox.io.vn/v1/json-validator" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"json":"{\"name\":\"Alice\",\"age\":-3}","schema":{"type":"object","required":["name","email"],"properties":{"name":{"type":"string"},"age":{"type":"integer","minimum":0}}}}'

const res = await fetch('https://apibox.io.vn/v1/json-validator', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "json": "{\"name\":\"Alice\",\"age\":-3}",
    "schema": {
      "type": "object",
      "required": [
        "name",
        "email"
      ],
      "properties": {
        "name": {
          "type": "string"
        },
        "age": {
          "type": "integer",
          "minimum": 0
        }
      }
    }
  }),
});
const data = await res.json();
console.log(data);

import requests

res = requests.post(
    "https://apibox.io.vn/v1/json-validator",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={"json": "{\"name\":\"Alice\",\"age\":-3}", "schema": {"type": "object", "required": ["name", "email"], "properties": {"name": {"type": "string"}, "age": {"type": "integer", "minimum": 0}}}},
    timeout=30,
)
print(res.json())

<?php
$ch = curl_init('https://apibox.io.vn/v1/json-validator');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_HTTPHEADER => ['Authorization: Bearer YOUR_API_KEY', 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS => '{"json":"{\\"name\\":\\"Alice\\",\\"age\\":-3}","schema":{"type":"object","required":["name","email"],"properties":{"name":{"type":"string"},"age":{"type":"integer","minimum":0}}}}',
]);
$response = curl_exec($ch);
print_r(json_decode($response, true));

API documentation → Get a free API key

FAQ

Which JSON Schema drafts are supported?

Draft 4, draft 7, 2019-09 and 2020-12 (default). Choose with the draft parameter.

How do I get the line number of a JSON syntax error?

Send the document as a string in json. When parsing fails, parse_error contains position, line and column when the parser reports them.

Can I validate syntax without a schema?

Yes. Omit schema; the response then only says whether the JSON is valid, with a note that no schema was given.