SPF record parser API
Reads one SPF record as text with the SPF check's parser (RFC 7208): version, mechanisms with qualifiers and values, modifiers, syntax errors and the all policy, and counts the terms that need DNS lookups. Includes are not followed; the SPF check on a domain does that.
POST https://api.lookproof.dev/v1/mail/spf-parse
Updated 2026-10-09
Examples use the Base (eip155:8453) network.
Input
A JSON body with content-type: application/json.
| Name | Type | Required | Limits | Description |
|---|---|---|---|---|
record | string | Yes | 1–4096 characters | The SPF record text, starting with v=spf1. |
Example request
curl -i -X POST https://api.lookproof.dev/v1/mail/spf-parse \
-H 'content-type: application/json' \
-d '{"record": "v=spf1 mx include:_spf.example.com ~all"}'import asyncio
import os
from eth_account import Account
from x402 import x402Client
from x402.http.clients import x402HttpxClient
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact import register_exact_evm_client
async def main() -> None:
signer = EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"]))
client = register_exact_evm_client(x402Client(), signer, networks="eip155:8453")
async with x402HttpxClient(client) as http:
response = await http.post('https://api.lookproof.dev/v1/mail/spf-parse', json={'record': 'v=spf1 mx include:_spf.example.com ~all'})
response.raise_for_status()
print(response.json())
asyncio.run(main())
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";
const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY);
const fetchWithPayment = wrapFetchWithPaymentFromConfig(fetch, {
schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }],
});
const response = await fetchWithPayment("https://api.lookproof.dev/v1/mail/spf-parse", {
method: "POST",
headers: { "content-type": "application/json" },
body: JSON.stringify({"record": "v=spf1 mx include:_spf.example.com ~all"}),
});
console.log(await response.json());
curl: unpaid request — returns 402 with the price (PAYMENT-REQUIRED). The Python and JavaScript clients pay it and send the request again. Only ordinary wallets (EOA) can pay; smart-contract wallets get a 402 without charge. See payments.
Example response
{
"checked_at": "2026-10-24T12:00:00Z",
"data": {
"all_qualifier": "~",
"dns_lookup_terms": 2,
"is_spf": true,
"notes": [
"Each include and redirect is counted once here; the records they point to can need more DNS lookups. The SPF check on a domain counts the whole tree."
],
"record": "v=spf1 mx include:_spf.example.com ~all",
"redirect": null,
"syntax_errors": [],
"terms": [
{
"kind": "mechanism",
"name": "mx",
"qualifier": null,
"raw": "mx",
"value": null
},
{
"kind": "mechanism",
"name": "include",
"qualifier": null,
"raw": "include:_spf.example.com",
"value": "_spf.example.com"
},
{
"kind": "mechanism",
"name": "all",
"qualifier": "~",
"raw": "~all",
"value": null
}
]
},
"endpoint": "mail.spf_parse",
"findings": [
{
"code": "SPF_SOFTFAIL_ALL",
"evidence": {
"count": 1,
"items": [
{
"term": "~all"
}
]
},
"explanation": "Receivers decide how to handle mail that does not match the policy.",
"message": "The SPF policy ends with softfail (~all).",
"recommendation": "Confirm that all legitimate senders are covered before changing the policy.",
"severity": "info"
}
],
"meta": {
"cache_hit": false,
"duration_ms": 42,
"fresh_until": "2026-10-24T12:05:00Z",
"observed_at": "2026-10-24T12:00:00Z",
"resolver": null,
"source": "offline"
},
"request_id": "req_aaaaaaaaaaaaaaaaaaaaaaaaaa",
"schema_version": "1.0",
"status": "info"
}
Response fields
| Field | Meaning |
|---|---|
request_id | Unique id of this request. Quote it when you contact support. |
endpoint | The endpoint id, for example mail.spf. |
schema_version | Version of the response format, currently 1.0. |
checked_at | When the check ran (ISO 8601, UTC). |
status | ok, info, warning or error from the worst finding, or unknown when the check was incomplete. unknown is not an error in the domain. |
data | The check's own data. Its fields are listed below. |
findings | What was found: code, severity, message, explanation and evidence. |
meta | Duration, cache use, resolver and how long the result stays fresh. |
Fields in data
| Field | Type |
|---|---|
record | string |
is_spf | boolean |
terms | array of SpfTerm |
syntax_errors | array of SpfSyntaxIssue |
all_qualifier | one of +, -, ~, ? or null |
redirect | string or null |
dns_lookup_terms | integer |
notes | array of string |
Status codes
| Status | Code | Meaning | Do you pay? |
|---|---|---|---|
| 200 | — | The result is delivered, also when it has negative findings. | Yes: charged once per payment; redelivery of the same payment is free |
| 402 | — | Payment is required, or the attached payment was refused. The body states the price. | No |
| 400 | bad_request | The request is malformed. | No |
| 409 | payment_in_progress, payment_bound_to_other_request | This payment is already being processed, or it is bound to a different request. No new payment is taken. | No |
| 413 | payload_too_large | The body is larger than 64 KB. | No |
| 422 | invalid_input | The input failed validation on a request that carries a payment; nothing is charged. Without a payment, invalid input gets a 402 whose error field names the problem. | No |
| 429 | rate_limited | Too many requests from this IP address or payer. | No |
| 502 | check_failed | The check could not be completed. | No |
| 503 | busy, unavailable, payments_unavailable | The service is busy or temporarily unavailable. | No |
| 504 | deadline_exceeded | The check ran out of time. | No |
Errors use the common error body. See errors.
Findings this endpoint can return
SPF (9)
- Info
SPF_MACRO_NOT_EVALUATEDAn SPF record contains macros that were not evaluated. - Warning
SPF_NEUTRAL_ALLThe SPF policy ends with ?all. - Error
SPF_NOT_SPF_RECORDThe text is not an SPF record: it does not start with v=spf1. - Warning
SPF_NO_ALLThe SPF record has no all mechanism and no redirect. - Error
SPF_PASS_ALLThe SPF policy ends with +all. - Warning
SPF_PTR_MECHANISMAn SPF record uses the ptr mechanism. - Info
SPF_SOFTFAIL_ALLThe SPF policy ends with softfail (~all). - Error
SPF_SYNTAX_ERRORAn SPF record contains a term that cannot be parsed. - Error
SPF_TOO_MANY_LOOKUPSThe SPF record needs more than 10 DNS lookups.