SPF Validator API Reference

Overview

SPF Validator reads the TXT records at `domain`, after stripping any scheme and leading `www.`, and keeps those starting with `v=spf1`. It then follows every `include:` and `redirect=` target breadth-first. Each domain is queried once, and the walk stops after 50 domains. `dns_lookups_num` is the number of domains queried along the way, not the RFC 7208 count of every `a`, `mx`, `ptr` and `exists` term.

Each record in `spf_records_list` carries its `origin`, the `record` text, `chars_num`, `use_macro` (true when a term contains `%{`), the `domains` it includes and the `authorized_ips` it lists. Only `ip4` and `ip6` terms with a pass qualifier count as authorized; `-ip4`, `~ip4` and `?ip4` are skipped. `authorized_ips` and `domains_extracted` combine them across the whole chain. `spf_record` is the root domain's record.

When you send `ip`, `ip_pass` is true if the address falls inside any authorized range, matched by address family and prefix length, or if it matches the A, AAAA or MX hosts named by `a` and `mx` terms (up to 10 such terms). An address that is not a valid IP returns `false`; without `ip`, the field is null.

`all_qualifier` reads the `all` term in the root record: `fail` for `-all`, `softfail` for `~all`, `neutral` for `?all`, `pass` for `+all` or a bare `all`, and null when there is none. `risk_score` is 70 with no record, 80 for `pass`, 50 for `neutral` or no `all`, 25 for `softfail` and 5 for `fail`, raised to at least 60 when more than 10 domains were queried. `spf_valid` means a record was found. A DNS failure on the root domain returns a 503. Results are cached for 15 minutes per domain and IP pair.

Live Test SPF Validator API →

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

GEThttps://api.apiverve.com/v1/spfvalidator

1
2

curl "https://api.apiverve.com/v1/spfvalidator?domain=myspace.com" \
  -H "x-api-key: your_api_key_here"

const res = await fetch('https://api.apiverve.com/v1/spfvalidator?domain=myspace.com', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

import requests

res = requests.get(
    "https://api.apiverve.com/v1/spfvalidator?domain=myspace.com",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/spfvalidator?domain=myspace.com", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Parameter	Type	Description
`domain`Required	string	The domain to validate the SPF record for domain

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "host": "myspace.com",
    "has_spf_record": true,
    "dns_lookups_num": 9,
    "spf_record": "v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.156.5/32 ip4:35.245.108.108/32 ip4:34.86.129.193/32 ip4:34.86.134.94/32 ip4:34.85.222.234/32 ip4:34.86…",
    "spf_records_list": [
      {
        "origin": "myspace.com",
        "record": "v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.156.5/32 ip4:35.245.108.108/32 ip4:34.86.129.193/32 ip4:34.86.134.94/32 ip4:34.85.222.234/32 ip4:34.86…",
        "chars_num": 637,
        "use_macro": false,
        "domains": [
          "_netblocks.mimecast.com"
        ],
        "authorized_ips": {
          "ipv4": [
            "63.208.226.34",
            "204.16.32.0/22",
            "67.134.143.0/24",
            "216.205.243.0/24",
            "34.85.156.5/32",
            "35.245.108.108/32",
            "34.86.129.193/32",
            "34.86.134.94/32",
            "34.85.222.234/32",
            "34.86.176.234/32",
            "34.86.125.212/32",
            "34.85.224.60/32",
            "34.86.160.49/32",
            "35.245.64.166/32",
            "35.188.226.11/32",
            "34.86.208.228/32",
            "34.85.216.144/32",
            "35.221.22.153/32",
            "34.86.137.108/32",
            "34.86.51.35/32",
            "34.150.221.40/32",
            "34.85.216.70/32",
            "34.86.37.191/32",
            "34.85.214.215/32",
            "35.236.234.82/32",
            "34.86.161.241/32",
            "216.32.181.16",
            "216.178.32.0/20",
            "168.235.224.0/24"
          ]
        }
      },
      {
        "origin": "_netblocks.mimecast.com",
        "record": "v=spf1 include:eu._netblocks.mimecast.com include:us._netblocks.mimecast.com include:za._netblocks.mimecast.com include:de._netblocks.mimecast.com include:au._netblocks.mimecast.com include:ca._netblo…",
        "chars_num": 257,
        "use_macro": false,
        "domains": [
          "eu._netblocks.mimecast.com",
          "us._netblocks.mimecast.com",
          "za._netblocks.mimecast.com",
          "de._netblocks.mimecast.com",
          "au._netblocks.mimecast.com",
          "ca._netblocks.mimecast.com",
          "usb._netblocks.mimecast.com"
        ]
      },
      {
        "origin": "eu._netblocks.mimecast.com",
        "record": "v=spf1 ip4:195.130.217.0/24 ip4:91.220.42.0/24 ip4:146.101.78.0/24 ip4:207.82.80.0/24 ip4:213.167.81.0/25 ip4:193.7.207.0/25 ip4:213.167.75.0/25 ip4:185.58.85.0/24 ip4:185.58.86.0/24 ip4:193.7.206.0/2…",
        "chars_num": 225,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "195.130.217.0/24",
            "91.220.42.0/24",
            "146.101.78.0/24",
            "207.82.80.0/24",
            "213.167.81.0/25",
            "193.7.207.0/25",
            "213.167.75.0/25",
            "185.58.85.0/24",
            "185.58.86.0/24",
            "193.7.206.0/25",
            "147.28.36.0/24"
          ]
        }
      },
      {
        "origin": "us._netblocks.mimecast.com",
        "record": "v=spf1 ip4:207.211.31.0/25 ip4:205.139.110.0/24 ip4:216.205.24.0/24 ip4:170.10.129.0/24 ip4:63.128.21.0/24 ip4:170.10.133.0/24 ip4:185.58.84.93/32 ip4:207.211.41.113/32 ip4:207.211.30.64/26 ip4:207.21…",
        "chars_num": 299,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "207.211.31.0/25",
            "205.139.110.0/24",
            "216.205.24.0/24",
            "170.10.129.0/24",
            "63.128.21.0/24",
            "170.10.133.0/24",
            "185.58.84.93/32",
            "207.211.41.113/32",
            "207.211.30.64/26",
            "207.211.30.128/25",
            "216.145.221.0/24",
            "170.10.128.0/24",
            "170.10.132.56/29",
            "170.10.132.64/29"
          ]
        }
      },
      {
        "origin": "za._netblocks.mimecast.com",
        "record": "v=spf1 ip4:41.74.192.0/22 ip4:41.74.200.0/23 ip4:41.74.196.0/22 ip4:41.74.204.0/23 ip4:41.74.206.0/24 ~all",
        "chars_num": 106,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "41.74.192.0/22",
            "41.74.200.0/23",
            "41.74.196.0/22",
            "41.74.204.0/23",
            "41.74.206.0/24"
          ]
        }
      },
      {
        "origin": "de._netblocks.mimecast.com",
        "record": "v=spf1 ip4:51.163.158.0/24 ip4:194.104.109.0/24 ip4:194.104.111.0/24 ip4:194.104.110.21/32 ip4:194.104.110.240/28 ip4:62.140.10.21/32 ip4:62.140.7.0/24 ip4:194.104.108.240/29 ip4:194.104.108.21/32 ip4…",
        "chars_num": 221,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "51.163.158.0/24",
            "194.104.109.0/24",
            "194.104.111.0/24",
            "194.104.110.21/32",
            "194.104.110.240/28",
            "62.140.10.21/32",
            "62.140.7.0/24",
            "194.104.108.240/29",
            "194.104.108.21/32",
            "51.163.159.0/24"
          ]
        }
      },
      {
        "origin": "au._netblocks.mimecast.com",
        "record": "v=spf1 ip4:103.13.69.0/24 ip4:124.47.150.0/24 ip4:124.47.189.0/24 ip4:103.96.23.0/24 ip4:103.96.21.0/24 ip4:180.189.28.0/24 ip4:216.145.217.0/24 ip4:103.96.22.96/28 ip4:103.96.22.22/32 ip4:103.96.20.2…",
        "chars_num": 229,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "103.13.69.0/24",
            "124.47.150.0/24",
            "124.47.189.0/24",
            "103.96.23.0/24",
            "103.96.21.0/24",
            "180.189.28.0/24",
            "216.145.217.0/24",
            "103.96.22.96/28",
            "103.96.22.22/32",
            "103.96.20.22/32",
            "103.96.20.96/28"
          ]
        }
      },
      {
        "origin": "ca._netblocks.mimecast.com",
        "record": "v=spf1 ip4:170.10.145.0/24 ip4:170.10.147.0/24 ip4:170.10.144.126/32 ip4:170.10.146.126/32 ip4:170.10.144.240/29 ip4:170.10.146.240/29 ip4:216.145.216.0/24 ~all",
        "chars_num": 160,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "170.10.145.0/24",
            "170.10.147.0/24",
            "170.10.144.126/32",
            "170.10.146.126/32",
            "170.10.144.240/29",
            "170.10.146.240/29",
            "216.145.216.0/24"
          ]
        }
      },
      {
        "origin": "usb._netblocks.mimecast.com",
        "record": "v=spf1 ip4:170.10.151.0/24 ip4:170.10.153.0/24 ip4:170.10.150.240/29 ip4:170.10.152.240/29 ip4:170.10.156.0/24 ip4:170.10.157.0/24 ~all",
        "chars_num": 135,
        "use_macro": false,
        "authorized_ips": {
          "ipv4": [
            "170.10.151.0/24",
            "170.10.153.0/24",
            "170.10.150.240/29",
            "170.10.152.240/29",
            "170.10.156.0/24",
            "170.10.157.0/24"
          ]
        }
      }
    ],
    "domains_extracted": [
      "myspace.com",
      "_netblocks.mimecast.com",
      "eu._netblocks.mimecast.com",
      "us._netblocks.mimecast.com",
      "za._netblocks.mimecast.com",
      "de._netblocks.mimecast.com",
      "au._netblocks.mimecast.com",
      "ca._netblocks.mimecast.com",
      "usb._netblocks.mimecast.com"
    ],
    "authorized_ips": {
      "ipv4": [
        "63.208.226.34",
        "204.16.32.0/22",
        "67.134.143.0/24",
        "216.205.243.0/24",
        "34.85.156.5/32",
        "35.245.108.108/32",
        "34.86.129.193/32",
        "34.86.134.94/32",
        "34.85.222.234/32",
        "34.86.176.234/32",
        "34.86.125.212/32",
        "34.85.224.60/32",
        "34.86.160.49/32",
        "35.245.64.166/32",
        "35.188.226.11/32",
        "34.86.208.228/32",
        "34.85.216.144/32",
        "35.221.22.153/32",
        "34.86.137.108/32",
        "34.86.51.35/32",
        "34.150.221.40/32",
        "34.85.216.70/32",
        "34.86.37.191/32",
        "34.85.214.215/32",
        "35.236.234.82/32",
        "34.86.161.241/32",
        "216.32.181.16",
        "216.178.32.0/20",
        "168.235.224.0/24",
        "195.130.217.0/24",
        "91.220.42.0/24",
        "146.101.78.0/24",
        "207.82.80.0/24",
        "213.167.81.0/25",
        "193.7.207.0/25",
        "213.167.75.0/25",
        "185.58.85.0/24",
        "185.58.86.0/24",
        "193.7.206.0/25",
        "147.28.36.0/24",
        "207.211.31.0/25",
        "205.139.110.0/24",
        "216.205.24.0/24",
        "170.10.129.0/24",
        "63.128.21.0/24",
        "170.10.133.0/24",
        "185.58.84.93/32",
        "207.211.41.113/32",
        "207.211.30.64/26",
        "207.211.30.128/25",
        "216.145.221.0/24",
        "170.10.128.0/24",
        "170.10.132.56/29",
        "170.10.132.64/29",
        "41.74.192.0/22",
        "41.74.200.0/23",
        "41.74.196.0/22",
        "41.74.204.0/23",
        "41.74.206.0/24",
        "51.163.158.0/24",
        "194.104.109.0/24",
        "194.104.111.0/24",
        "194.104.110.21/32",
        "194.104.110.240/28",
        "62.140.10.21/32",
        "62.140.7.0/24",
        "194.104.108.240/29",
        "194.104.108.21/32",
        "51.163.159.0/24",
        "103.13.69.0/24",
        "124.47.150.0/24",
        "124.47.189.0/24",
        "103.96.23.0/24",
        "103.96.21.0/24",
        "180.189.28.0/24",
        "216.145.217.0/24",
        "103.96.22.96/28",
        "103.96.22.22/32",
        "103.96.20.22/32",
        "103.96.20.96/28",
        "170.10.145.0/24",
        "170.10.147.0/24",
        "170.10.144.126/32",
        "170.10.146.126/32",
        "170.10.144.240/29",
        "170.10.146.240/29",
        "216.145.216.0/24",
        "170.10.151.0/24",
        "170.10.153.0/24",
        "170.10.150.240/29",
        "170.10.152.240/29",
        "170.10.156.0/24",
        "170.10.157.0/24"
      ],
      "ipv6": []
    },
    "issues_found": [],
    "spf_valid": true,
    "has_issues": false,
    "macros_found": false,
    "ip_pass": false,
    "elapsed_ms": 431,
    "all_qualifier": "fail",
    "risk_score": 5,
    "risk_level": "low"
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`host`	string	`"myspace.com"`	The domain name being validated
`has_spf_record`	boolean	`true`	Whether the domain has SPF record
`dns_lookups_num`Premium	number	`9`	Total number of DNS lookups performed
`spf_record`	string	`"v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.15…"`	The complete SPF record string
`spf_records_list`Premium	array[9]		List of SPF records with detailed parsing
`origin`Premium	string	`"myspace.com"`	Domain origin of SPF record
`record`Premium	string	`"v=spf1 mx ip4:63.208.226.34 ip4:204.16.32.0/22 ip4:67.134.143.0/24 ip4:216.205.243.0/24 ip4:34.85.15…"`	Full SPF record content
`chars_num`Premium	number	`637`	Character count of SPF record
`use_macro`Premium	boolean	`false`	Whether record uses macros
`domains`Premium	array	`[_netblocks.mimecast.com]`	Domains referenced in SPF record
`authorized_ips`Premium	object	`{...}`	All IP addresses authorized by SPF
`ipv4`Premium	array	`[63.208.226.34, ...]`	IPv4 addresses authorized to send mail
`domains_extracted`Premium	array	`[myspace.com, ...]`	All domains found in SPF chain
`authorized_ips`Premium	object	`{...}`	All IP addresses authorized by SPF
`ipv4`Premium	array	`[63.208.226.34, ...]`	All IPv4 addresses authorized by SPF
`ipv6`Premium	array	`[]`	All IPv6 addresses authorized by SPF
`issues_found`Premium	array	`[]`	List of SPF validation issues
`spf_valid`	boolean	`true`	Whether SPF record is valid
`has_issues`	boolean	`false`	Whether validation found issues
`macros_found`Premium	boolean	`false`	Whether SPF record uses macros
`ip_pass`	boolean	`false`	Whether IP passes SPF check
`elapsed_ms`Premium	number	`431`	Validation processing time in milliseconds
`all_qualifier`	string	`"fail"`	The qualifier on the SPF 'all' mechanism: fail (-all, strict), softfail (~all), neutral (?all) or pass (+all, authorizes any sender). Null when the record has no all mechanism (e.g. defers via redirect)
`risk_score`Premium	number	`5`	Composite 0-100 email-spoofing risk based on the SPF enforcement qualifier and DNS-lookup limit — higher means the domain is more easily spoofed (no SPF or +all scores high; -all scores low)
`risk_level`Premium	string	`"low"`	Risk band derived from the score: low, medium or high

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted	A key restriction or IP allow-list; see key scoping.
`429`	Rate limited, or out of credits	Read `error` to tell them apart; see rate limits.

Use cases

Outbound Mail Onboarding: Before sending campaign blasts, marketing platforms check customer sender domains to confirm a valid SPF record exists and inspect the all-mechanism qualifier.
Mail Gateway Threat Screening: When incoming messages arrive, mail security gateways test the relay IP against the sender domain's SPF record to flag unauthorized server relays.
DNS Configuration Auditing: Flag syntax errors and missing SPF records across managed domains so IT administrators fix broken mail authentication settings before delivery rates drop.
Sales Outreach Health Checks: Sales engagement tools query sending IP authorization across connected mailboxes to prevent cold outreach from landing in recipient spam folders.

Other ways to use SPF Validator

Set up SPF Validator on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →

Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContext →Reference →

SPF Validator