Monitor a list of domains on a schedule

POST/api/v1/email/domain-monitors

authentication: Secret API key as a bearer token
billing: Creation is free. Each run bills every domain like one domain lookup: 1 credit when the domain accepts mail; dead and invalid domains and 7-day repeats are free, so a domain is billed at most once a week whatever the cadence.

Saves up to 500 domains — your own sending domains, or the domains your list is full of — and re-checks them every day, week or month through the domain endpoint. Domains are lowercased, converted to punycode and deduplicated. The first run starts right away and only sets the baseline; from the next run on, every domain that changes mail provider, loses its SPF, DMARC, DKIM keys or MTA-STS policy, is parked, lands its mail hosts on a threat blocklist, has a registration ending within 30 days, or stops accepting mail is reported to the account's email with the reason.

Answers 201 with the monitor. The baseline run is queued, not finished: poll the monitor for last_run_at and last_summary.

With a webhook_url, a finished run is POSTed there as { "event": "domain_monitor.run", "monitor": { "id", "name", "cadence", "last_run_at", "next_run_at" }, "summary": { … the same block as last_summary … }, "changes": [ … ] }, where changes names the domains the alert email names. The X-Spaw-Signature-V2 header carries t={unix seconds},v2={lowercase hex}, where the hex is the HMAC-SHA256 of v2:{t}:{raw body} keyed with webhook_secret, which this response returns once; the original X-Spaw-Signature is sent beside it until 1 March 2027. Connection errors and 5xx answers are retried twice, and the outcome is readable afterwards as webhook_status and webhook_detail. A URL that resolves onto a private network is never posted to.

Request body

field	type	description
namerequired	string	A label for the alerts. At most 100 characters.
domainsrequired	string[]	1 to 500 domain names. Spellings of one domain (case, a trailing dot, an internationalised form) count once; anything that is not a hostname answers 422 naming the entry.
cadencerequired	string	How often the list is re-checked. One of: daily, weekly, monthly.
webhook_url	string \| null	An https URL every reported run is POSTed to. The signing secret is returned once, in this response, and never again. At most 2,048 characters.
webhook_events	string	When to post. `changes` posts only when the run found something new or stopped early; `every_run` posts after every run. One of: changes, every_run. Default: changes.

Example request

curl -X POST https://spaw.co/api/v1/email/domain-monitors \
  -H "Authorization: Bearer sk_live_…" \
  -H "Content-Type: application/json" \
  -d '{
  "name": "Sending domains",
  "domains": [
    "acme.com",
    "news.acme.com"
  ],
  "cadence": "daily"
}'

const response = await fetch('https://spaw.co/api/v1/email/domain-monitors', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer sk_live_…',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "name": "Sending domains",
    "domains": [
      "acme.com",
      "news.acme.com"
    ],
    "cadence": "daily"
  }),
});
const result = await response.json();

import requests

response = requests.post(
    'https://spaw.co/api/v1/email/domain-monitors',
    headers={'Authorization': 'Bearer sk_live_…'},
    json={
        'name': 'Sending domains',
        'domains': [
            'acme.com',
            'news.acme.com'
        ],
        'cadence': 'daily'
    },
)
result = response.json()

$ch = curl_init('https://spaw.co/api/v1/email/domain-monitors');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_HTTPHEADER => ['Authorization: Bearer sk_live_…', 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS => json_encode([
        'name' => 'Sending domains',
        'domains' => [
            'acme.com',
            'news.acme.com'
        ],
        'cadence' => 'daily'
    ]),
]);
$result = json_decode(curl_exec($ch), true);

from spaw import Client

client = Client('sk_live_…')
result = client.create_domain_monitor(name='Sending domains', domains=[
    'acme.com',
    'news.acme.com'
], cadence='daily')

import Spaw from 'spaw';

const spaw = new Spaw({ apiKey: 'sk_live_…' });
const result = await spaw.createDomainMonitor({
    name: 'Sending domains',
    domains: [
        'acme.com',
        'news.acme.com'
    ],
    cadence: 'daily'
});

use Spaw\Client;

$spaw = new Client('sk_live_…');
$result = $spaw->createDomainMonitor(name: 'Sending domains', domains: [
    'acme.com',
    'news.acme.com'
], cadence: 'daily');

This endpoint has no console on its page. It writes to your account. A documentation page can show you the request; making the change is for the dashboard or for a call you make yourself.

Responses

201The monitor was saved and its baseline run queued.

{
    "success": true,
    "data": {
        "monitor": {
            "id": 4,
            "name": "Sending domains",
            "cadence": "daily",
            "domain_count": 2,
            "next_run_at": "2026-09-14T10:12:44+00:00",
            "last_run_at": null,
            "last_summary": null,
            "webhook_url": null,
            "webhook_events": "changes",
            "webhook_status": null,
            "webhook_detail": null,
            "prunes_after_days": 365,
            "created_at": "2026-09-13T10:12:44+00:00",
            "webhook_secret": null
        }
    }
}

401The key is missing, malformed, or revoked.

{
    "success": false,
    "error": {
        "code": "UNAUTHENTICATED",
        "message": "Provide a valid API key as a bearer token.",
        "request_id": "req_01m1kgdm4xngzmbmff68g94w0c"
    }
}

422The request body could not be validated; `error.errors` lists the fields.

{
    "success": false,
    "error": {
        "code": "VALIDATION_FAILED",
        "message": "The email field is required.",
        "errors": {
            "email": [
                "The email field is required."
            ]
        },
        "request_id": "req_01m1kgdm4xngzmbmff68g94w0c"
    }
}

429Over 5 requests per second for the key. Retry after the limit resets.

{
    "success": false,
    "error": {
        "code": "RATE_LIMITED",
        "message": "Too many requests. Retry after the limit resets.",
        "request_id": "req_01m1kgdm4xngzmbmff68g94w0c"
    }
}

Error codes

Failures answer { success: false, error: { code, message, request_id } }. Each code has its own page.

markdown version·openapi.json