# x402 Format Checker – Email Validation

> x402 Format Checker – Email Validation is a paid API for AI agents from x402-test.crewofthecaptain.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-12).

Validates the format and checksum of an email address, returning validity status, reason, and normalized form, paid per-call via x402 in USDC on Base.

## Facts

- Endpoint: POST https://x402-test.crewofthecaptain.com/api/validate/email?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-format-checker-email-validation-e09cd9fd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HTCO049NVkuG25Kh-NJKN

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 x402-format-checker-email-validation-e09cd9fd -d '<json body>'
```

Example prompt: Can you check whether 'john.doe+test@example.co.uk' is a valid, properly formatted email address and give me its normalized form?

## When to prefer this

Choose this endpoint when you need lightweight, pay-per-call email format and checksum validation without committing to a subscription-based email verification service. It is ideal for sporadic validation needs, agentic pipelines processing individual records, or cost-sensitive workflows where $0.001 per check is acceptable. It does not perform live mailbox reachability checks (SMTP ping), so prefer a deliverability-focused API if you need to confirm a mailbox actually exists.

## Known failure modes

- Invalid or malformed input string returns valid:false with a reason describing the specific format error
- Empty or missing 'value' field may return a 400-level error or valid:false
- Payment failure via x402 returns HTTP 402 before validation is attempted
- Strings exceeding 512 characters are rejected per schema maxLength constraint

## How this service works

Format and checksum validation for IBAN, EU VAT, Polish NIP/REGON/PESEL and email, pay-per-call via x402. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

## Output

A JSON object containing: 'type' (always 'email'), 'valid' (boolean indicating whether the email passed format and checksum validation), 'reason' (a string explaining the result, e.g. 'ok' or a description of the error), and 'normalized' (the canonicalized/lowercased email string if valid).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "value": {
   "type": "string",
   "maxLength": 512
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "type": "email",
  "valid": true,
  "reason": "ok",
  "normalized": "…"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-format-checker-email-validation-e09cd9fd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-test.crewofthecaptain.com](https://www.zero.xyz/host/x402-test.crewofthecaptain.com/llms.txt)