# Email SPF Alignment Check

> Email SPF Alignment Check is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Checks relaxed or strict SPF domain alignment between the RFC5321 MAIL FROM domain and the RFC5322 From domain, returning a deterministic pass/advisory result.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/email-spf-alignment-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/email-spf-alignment-check-e83fa259
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mQJinJIPwTBcn5_nb4m8o

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 email-spf-alignment-check-e83fa259 -d '<json body>'
```

Example prompt: Check the SPF alignment for an email where the From domain is example.com and the MAIL FROM domain is mail.example.com — use relaxed mode and tell me if it passes.

## When to prefer this

Use this endpoint when you need a stateless, deterministic, first-party SPF alignment check without calling an external DNS resolver or email authentication service. It is ideal for DMARC policy enforcement pipelines, pre-send email validation, and diagnosing alignment mismatches between envelope and header sender domains. Prefer this over full DMARC evaluation tools when you only need the SPF alignment component in isolation.

## Known failure modes

- Missing or malformed from_domain or mail_from_domain returns a validation error
- Invalid mode value (not 'relaxed' or 'strict') may return an error or default behavior
- Domains exceeding maxLength constraints may be rejected
- Payment failure via x402 protocol will prevent endpoint access

## How this service works

Email SPF Alignment Check: Email SPF Alignment Check checks relaxed or strict SPF domain alignment from bounded caller-supplied values without an external provider. Call Email SPF Alignment Check before accepting, caching, redirecting, or retrying a caller-supplied web response. Returns normalized web evidence, the computed finding, and an explicit pass or advisory status for Email SPF Alignment Check as versioned deterministic JSON. Price: $0.001 USDC via x402 on Base. First-party, stateless,…

## Output

Returns a versioned deterministic JSON object containing: normalized domain evidence for both input domains, the computed SPF alignment finding (pass or fail), and an explicit pass or advisory status. All processing is stateless and in-memory with no data retention.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "mode": {
   "type": "string",
   "maxLength": 8192,
   "description": "Mode supplied to Email SPF Alignment Check; used only for this bounded calculation and processed in memory without retention."
  },
  "from_domain": {
   "type": "string",
   "maxLength": 8192,
   "description": "From Domain supplied to Email SPF Alignment Check; used only for this bounded calculation and processed in memory without retention."
  },
  "mail_from_domain": {
   "type": "string",
   "maxLength": 8192,
   "description": "Mail From Domain supplied to Email SPF Alignment Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "mode": "relaxed",
   "aligned": true
  },
  "schema": "delx/util-email-spf-alignment-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "ea586d1c403c2ce4bdabccfde8d16390a6f39bd162622d5aa8ca6b864aa2c9de",
   "external_calls": 0
  },
  "operation": "web_reliability:email_spf_alignment_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-spf-alignment-check-e83fa259/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)