# Domain Intel SPF Lookup — pay-per-call via x402

> Domain Intel SPF Lookup — pay-per-call via x402 is a paid API for AI agents from dns.halowerk.com, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-12).

Looks up SPF (mail policy) and comprehensive domain intelligence including WHOIS, DNS, TLS certificate, and subdomains for a given domain, paid per call in USDC over x402.

## Facts

- Endpoint: POST https://dns.halowerk.com/domain/articles/spf-lookup-budget?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/domain-intel-spf-lookup-pay-per-call-via-x402-d6604e35
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_535TkBh4zamtySWnjqyia

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability domain-intel-spf-lookup-pay-per-call-via-x402-d6604e35 -d '<json body>'
```

Example prompt: Can you look up the SPF record and full domain intelligence — WHOIS, DNS, TLS cert, and any subdomains — for halowerk.com?

## When to prefer this

Choose this endpoint when you need a single, no-signup, pay-per-call source for comprehensive domain intelligence — especially SPF/mail policy — without managing API keys or subscriptions. Ideal for agents running ad-hoc domain investigations, security audits, or email deliverability checks at low volume where the $0.009/call micropayment model is cost-effective.

## Known failure modes

- Invalid domain format — rejected by input pattern validation before the call is made
- Domain does not exist or is not resolvable — may return empty or partial results
- TLS certificate unavailable for domains without HTTPS
- WHOIS data redacted for privacy-protected registrations
- Subdomain enumeration may be incomplete depending on DNS configuration
- Payment failure or insufficient USDC balance causes 402 rejection

## How this service works

Domain in, WHOIS, DNS, mail policy, TLS certificate and subdomains out. Pay per call in USDC over x402. No signup, no API key.

## Output

Returns comprehensive domain intelligence for the queried domain, including SPF and other mail policy records, WHOIS registration data, DNS records, TLS/SSL certificate details, and discovered subdomains. Payment is deducted per call in USDC via the x402 protocol.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "domain": {
   "type": "string",
   "pattern": "^(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\\.)+[a-zA-Z]{2,63}$",
   "maxLength": 253
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/domain-intel-spf-lookup-pay-per-call-via-x402-d6604e35/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dns.halowerk.com](https://www.zero.xyz/host/dns.halowerk.com/llms.txt)