Email Domain Check

Checks the domain behind an email address: MX records, SPF and DMARC policies, and whether the address uses a disposable domain, a free mailbox provider or a role mailbox such as info@ or support@. It never contacts the mail server, so it cannot confirm that a mailbox exists.

POST https://YOUR_API_HOST/v1/email-domain-check

Credits and caching

• Success billing. 1 credit per address checked. You are charged only when the lookup finds something; a not-found result is free.
• Results are cached per account for 7 days. Repeating the same lookup in that window is free and returns cache_hit: true.
• Invalid input, rate limits and errors are never charged.
• Read the billing rules for the full picture.

Request

Send a JSON body with Authorization: Bearer <key>. The body can be up to 64 KB.

Example request

curl -X POST https://YOUR_API_HOST/v1/email-domain-check \
  -H "Authorization: Bearer $LOOKVALID_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"email":"info@example.com"}'

1const response = await fetch("https://YOUR_API_HOST/v1/email-domain-check", {
2  method: "POST",
3  headers: {
4    Authorization: `Bearer ${process.env.LOOKVALID_API_KEY}`,
5    "Content-Type": "application/json",
6  },
7  body: JSON.stringify({
8    "email": "info@example.com"
9  }),
10});
11​
12const result = await response.json();
13if (!response.ok) throw new Error(`${result.error.code}: ${result.error.fix}`);
14console.log(result.found, result.data, result.credits_charged);

1import os
2import requests
3​
4response = requests.post(
5    "https://YOUR_API_HOST/v1/email-domain-check",
6    headers={"Authorization": f"Bearer {os.environ['LOOKVALID_API_KEY']}"},
7    json={
8        "email": "info@example.com",
9    },
10    timeout=30,
11)
12result = response.json()
13if not response.ok:
14    raise RuntimeError(f"{result['error']['code']}: {result['error']['fix']}")
15print(result["found"], result["data"], result["credits_charged"])

Response

The status is 200 whether or not anything was found. Check found. Every response also carries the X-Request-Id, X-Credits-Charged, X-Credits-Remaining and X-RateLimit-* headers.

Envelope

The data object

Present when found is true, otherwise null.

Captured example (2026-10-18)

A real run of this lookup on 2026-10-18, using the request above, which is a public input. The envelope fields are left out.

1{
2  "product": "email-domain-check",
3  "found": true,
4  "data": {
5    "email": "info@example.com",
6    "syntax_valid": true,
7    "domain": "example.com",
8    "mx_records": [],
9    "has_mx": false,
10    "null_mx": true,
11    "implicit_mx": false,
12    "spf": {
13      "record": "v=spf1 -all",
14      "record_count": 1,
15      "policy": "-all",
16      "valid": true,
17      "issues": []
18    },
19    "dmarc": {
20      "record": "v=DMARC1;p=reject;sp=reject;adkim=s;aspf=s",
21      "record_count": 1,
22      "policy": "reject",
23      "subdomain_policy": "reject",
24      "pct": null,
25      "rua": [],
26      "valid": true,
27      "issues": []
28    },
29    "disposable": false,
30    "free_provider": false,
31    "role_account": true,
32    "smtp_checked": false,
33    "deliverability_signal": "undeliverable",
34    "deliverability_reasons": [
35      {
36        "code": "null_mx",
37        "message": "The domain publishes a null MX record, which means it does not accept email."
38      },
39      {
40        "code": "role_account",
41        "message": "The address is a shared role mailbox such as info@ or support@, not a person."
42      }
43    ]
44  },
45  "sources": [
46    "Public DNS (MX, TXT)",
47    "Open disposable-email-domain and free-provider lists"
48  ]
49}

Errors

• 400 invalid_input: The request input is invalid.
• 401 unauthorized: The API key is missing, malformed, revoked or unknown.
• 402 insufficient_credits: The account does not have enough credits for this lookup. Error code: insufficient_credits. During a trial whose allowance is used up the code is trial_allowance_exhausted: nothing is charged and the customer starts the plan from the billing page.
• 405 method_not_allowed: This endpoint does not accept that HTTP method.
• 413 payload_too_large: The request body is too large.
• 429 rate_limited: Too many requests for this API key.
• 500 internal_error: An unexpected error occurred.
• 503 provider_unavailable: The data source for this product is unavailable right now.