Clean, filter, flatten, and reshape API JSON payloads
Clean, filter, flatten, and reshape API JSON payloads using JSONPath expressions for Zapier workflows
Request
- x-api-key: <your-api-key>
- Content-Type: application/json
Response
{
"isFlattened": true,
"matchCount": 3,
"status": "success",
"tokensDeducted": 1,
"transformedData": "<transformed data>"
}What it does
Clean, filter, flatten, and reshape API JSON payloads using JSONPath expressions for Zapier workflows
Request
Body
| Field | Type | Required | Description |
|---|---|---|---|
arrayOutput | enum | no | Formatting rule if transformation yields an array result One of: array, first, last, join_comma, join_newline. |
flatten | boolean | no | Flatten nested JSON structures into single-level dot notation keys |
omit | array<string> | no | Array of property names to blacklist/remove from the output object |
payload | object | array<any> | yes | The raw JSON object or array to transform |
pick | array<string> | no | Array of property names to whitelist in the output object |
query | string | no | JSONPath / Dot-notation extraction query (e.g. "data.users[*].email" or "items[?status==active]") |
rename | object | no | Key-value map to rename keys in the result (e.g. {"user_email": "email"}) |
Example request
{
"arrayOutput": "array",
"flatten": false,
"omit": [
"<omit>"
],
"payload": {},
"pick": [
"<pick>"
],
"query": "castomapi",
"rename": {
"key": "example"
}
}Response
| Field | Type | Description |
|---|---|---|
isFlattened | boolean | |
matchCount | integer | |
status | string | |
tokensDeducted | integer | |
transformedData | any |
Example response
{
"isFlattened": true,
"matchCount": 3,
"status": "success",
"tokensDeducted": 1,
"transformedData": "<transformed data>"
}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/zapier/transform' \
-H 'x-api-key: <your-api-key>' \
-H 'Content-Type: application/json' \
-d '{"arrayOutput": "array", "flatten": false, "omit": ["<omit>"], "payload": {}, "pick": ["<pick>"], "query": "castomapi", "rename": {"key": "example"}}'const res = await fetch('https://app.castomapi.com/v1/zapier/transform', {
method: 'POST',
headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
body: JSON.stringify({"arrayOutput": "array", "flatten": false, "omit": ["<omit>"], "payload": {}, "pick": ["<pick>"], "query": "castomapi", "rename": {"key": "example"}})
});
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/zapier/transform', {
method: 'POST',
headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
body: JSON.stringify({"arrayOutput": "array", "flatten": false, "omit": ["<omit>"], "payload": {}, "pick": ["<pick>"], "query": "castomapi", "rename": {"key": "example"}})
});
const data = await res.json();
console.log(data);import requests
res = requests.post(
'https://app.castomapi.com/v1/zapier/transform',
headers={'x-api-key': '<your-api-key>'},
json={"arrayOutput": "array", "flatten": False, "omit": ["<omit>"], "payload": {}, "pick": ["<pick>"], "query": "castomapi", "rename": {"key": "example"}},
timeout=30,
)
print(res.json())<?php
$ch = curl_init('https://app.castomapi.com/v1/zapier/transform');
curl_setopt_array($ch, [
CURLOPT_CUSTOMREQUEST => 'POST',
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => ['x-api-key: <your-api-key>', 'Content-Type: application/json'],
CURLOPT_POSTFIELDS => json_encode(['arrayOutput' => 'array', 'flatten' => false, 'omit' => ['<omit>'], 'payload' => [], 'pick' => ['<pick>'], 'query' => 'castomapi', 'rename' => ['key' => 'example']]),
]);
$data = json_decode(curl_exec($ch), true);
print_r($data);Cost and limits
This operation costs 1 token. A call that fails is never billed. Every account gets 1000 free tokens a month; paid balances never expire.
Rate limits per minute
| No key | 10 |
| Free | 60 |
| Pro | 300 |
| Enterprise | 1200 |
Questions
What does Clean, filter, flatten, and reshape API JSON payloads cost?
1 token per successful call, debited from your wallet after the response. Failed calls are free. Every account receives 1000 free tokens a month.
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