Inline circuit breaker to prevent runaway Zap loops
Inline circuit breaker to prevent runaway Zap loops, webhook cycles, or infinite retries from draining token balances
Request
- x-api-key: <your-api-key>
- Content-Type: application/json
Response
{
"allowed": true,
"circuitTripped": true,
"currentWindowUsage": 39,
"maxTokensPerWindow": 5,
"message": "Hello from castomAPI.",
"remainingBudget": 21,
"resetInSeconds": 37,
"status": "success",
"tokensDeducted": 1,
"windowMinutes": 12,
"zapId": "zap_102826"
}What it does
Inline circuit breaker to prevent runaway Zap loops, webhook cycles, or infinite retries from draining token balances
Request
Body
| Field | Type | Required | Description |
|---|---|---|---|
autoTrip | boolean | no | If true, automatically returns HTTP 429 when budget is exceeded to abort downstream steps |
maxTokensPerWindow | integer | yes | Maximum allowed tokens consumed by this specific Zap inside the sliding time window |
tokensRequested | integer | no | Token cost of the upcoming operation about to be executed |
windowMinutes | integer | no | Sliding time window in minutes (1 to 1440 mins / 24 hrs) |
zapId | string | yes | Unique Zap identifier or workflow execution ID |
Example request
{
"autoTrip": true,
"maxTokensPerWindow": 5,
"tokensRequested": 1,
"windowMinutes": 60,
"zapId": "zap_102826"
}Response
| Field | Type | Description |
|---|---|---|
allowed | boolean | |
circuitTripped | boolean | |
currentWindowUsage | integer | |
maxTokensPerWindow | integer | |
message | string | |
remainingBudget | integer | |
resetInSeconds | integer | |
status | string | |
tokensDeducted | integer | |
windowMinutes | integer | |
zapId | string |
Example response
{
"allowed": true,
"circuitTripped": true,
"currentWindowUsage": 39,
"maxTokensPerWindow": 5,
"message": "Hello from castomAPI.",
"remainingBudget": 21,
"resetInSeconds": 37,
"status": "success",
"tokensDeducted": 1,
"windowMinutes": 12,
"zapId": "zap_102826"
}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/budget/guard' \
-H 'x-api-key: <your-api-key>' \
-H 'Content-Type: application/json' \
-d '{"autoTrip": true, "maxTokensPerWindow": 5, "tokensRequested": 1, "windowMinutes": 60, "zapId": "zap_102826"}'const res = await fetch('https://app.castomapi.com/v1/zapier/budget/guard', {
method: 'POST',
headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
body: JSON.stringify({"autoTrip": true, "maxTokensPerWindow": 5, "tokensRequested": 1, "windowMinutes": 60, "zapId": "zap_102826"})
});
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/budget/guard', {
method: 'POST',
headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
body: JSON.stringify({"autoTrip": true, "maxTokensPerWindow": 5, "tokensRequested": 1, "windowMinutes": 60, "zapId": "zap_102826"})
});
const data = await res.json();
console.log(data);import requests
res = requests.post(
'https://app.castomapi.com/v1/zapier/budget/guard',
headers={'x-api-key': '<your-api-key>'},
json={"autoTrip": True, "maxTokensPerWindow": 5, "tokensRequested": 1, "windowMinutes": 60, "zapId": "zap_102826"},
timeout=30,
)
print(res.json())<?php
$ch = curl_init('https://app.castomapi.com/v1/zapier/budget/guard');
curl_setopt_array($ch, [
CURLOPT_CUSTOMREQUEST => 'POST',
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => ['x-api-key: <your-api-key>', 'Content-Type: application/json'],
CURLOPT_POSTFIELDS => json_encode(['autoTrip' => true, 'maxTokensPerWindow' => 5, 'tokensRequested' => 1, 'windowMinutes' => 60, 'zapId' => 'zap_102826']),
]);
$data = json_decode(curl_exec($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 Inline circuit breaker to prevent runaway Zap loops 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