Validate JSON data against a JSON Schema
Validate JSON data against a JSON Schema, enforce structure with type coercion/property stripping, or auto-generate a JSON Schema from data
Request
- x-api-key: <your-api-key>
- Content-Type: application/json
Response
{
"enforcedData": "<enforced data>",
"errors": [],
"errorsCount": 3,
"mode": "validation",
"schema": {},
"status": "success",
"tokensDeducted": 1,
"valid": true
}What it does
Validate JSON data against a JSON Schema, enforce structure with type coercion/property stripping, or auto-generate a JSON Schema from data
Request
Body
| Field | Type | Required | Description |
|---|---|---|---|
data | any | yes | Target data (object, array, or stringified JSON) to validate or infer schema from |
options | object | no | |
↳ all_errors | boolean | no | |
↳ coerce_types | boolean | no | |
↳ remove_additional | boolean | no | |
↳ use_defaults | boolean | no | |
schema | object | no | Optional JSON Schema (Draft 07 / 2020-12). If omitted, a schema will be automatically inferred from data. |
Example request
{
"data": "<data>",
"options": {},
"schema": {}
}Response
| Field | Type | Description |
|---|---|---|
enforcedData | any | Data after coercion, default filling, or additional property removal |
errors | array<object> | |
↳ keyword | string | |
↳ message | string | |
↳ params | object | |
↳ path | string | |
errorsCount | integer | |
mode | enum | One of: validation, inference. |
schema | object | |
status | string | |
tokensDeducted | integer | |
valid | boolean |
Example response
{
"enforcedData": "<enforced data>",
"errors": [],
"errorsCount": 3,
"mode": "validation",
"schema": {},
"status": "success",
"tokensDeducted": 1,
"valid": true
}Errors
Every error answers with the same envelope: an HTTP status, a machine code and a sentence.
400 | The body or a parameter failed validation. The details array names the field. |
401 | No key, a revoked key or a wrong header. Send x-api-key. |
402 | The wallet cannot cover this call. Top up or wait for the monthly grant. |
404 | The resource does not exist, or it is not yours. Both answer identically and cost nothing. |
429 | Over the per-minute quota of your tier. Back off and retry. |
5xx | Upstream refused or timed out. The call is not billed. |
Code
curl -X POST 'https://app.castomapi.com/v1/parse/json-schema' \
-H 'x-api-key: <your-api-key>' \
-H 'Content-Type: application/json' \
-d '{"data": "<data>", "options": {}, "schema": {}}'const res = await fetch('https://app.castomapi.com/v1/parse/json-schema', {
method: 'POST',
headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
body: JSON.stringify({"data": "<data>", "options": {}, "schema": {}})
});
const data = await res.json();
console.log(data);import { request } from 'node:https';
// Node 18+ has fetch built in
const res = await fetch('https://app.castomapi.com/v1/parse/json-schema', {
method: 'POST',
headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
body: JSON.stringify({"data": "<data>", "options": {}, "schema": {}})
});
const data = await res.json();
console.log(data);import requests
res = requests.post(
'https://app.castomapi.com/v1/parse/json-schema',
headers={'x-api-key': '<your-api-key>'},
json={"data": "<data>", "options": {}, "schema": {}},
timeout=30,
)
print(res.json())<?php
$ch = curl_init('https://app.castomapi.com/v1/parse/json-schema');
curl_setopt_array($ch, [
CURLOPT_CUSTOMREQUEST => 'POST',
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => ['x-api-key: <your-api-key>', 'Content-Type: application/json'],
CURLOPT_POSTFIELDS => json_encode(['data' => '<data>', 'options' => [], 'schema' => []]),
]);
$data = json_decode(curl_exec($ch), true);
print_r($data);Cost and limits
This operation needs no API key and costs nothing: called without a key it answers 200 and deducts zero tokens, up to 10 requests a minute per IP address.
Rate limits per minute
| No key | 10 |
| Free | 60 |
| Pro | 300 |
| Enterprise | 1200 |
Questions
What does Validate JSON data against a JSON Schema cost?
This operation needs no API key and costs nothing: called without a key it answers 200 and deducts zero tokens, up to 10 requests a minute per IP address.
How do I authenticate?
Send your key in the x-api-key header. One key covers every metered endpoint; there is nothing to enable per endpoint.
Can I send an Authorization: Bearer token instead?
Not for a metered endpoint — those take the x-api-key header and nothing else. Bearer tokens belong to the account side: the dashboard and account APIs accept a JWT session, and castomapi-auth issues those through a standard OAuth2 handshake, with authorization code, client credentials and refresh grants. The auth service page covers it.
What are the limits?
10 requests a minute per IP with no key at all, 60 a minute on the free tier, 300 on Pro, 1200 on Enterprise. Above the no-key tier the quota is per account, across every endpoint.
OpenAPI: https://app.castomapi.com/docs/json