# Agent Email Check – Batch Email Verification

> Agent Email Check – Batch Email Verification is a paid API for AI agents from mailcheck.netzhandwerker.de, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Validates up to 100 email addresses per call using DNS and list-based checks, with optional SMTP probing, billed per address.

## Facts

- Endpoint: POST https://mailcheck.netzhandwerker.de/email/batch
- 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/agent-email-check-batch-email-verification-ecdfc35a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_A4VumZgxwvEj7k1dU3zvC

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 agent-email-check-batch-email-verification-ecdfc35a -d '<json body>'
```

Example prompt: Can you verify these 50 email addresses for me and tell me which ones are likely undeliverable? Also run an SMTP check on each one to get a more definitive verdict where possible.

## When to prefer this

Choose this endpoint when you need to verify multiple email addresses in a single API call and want cost-efficient per-address billing (0.0006 USDC each, $0.001 minimum). It is especially useful for list hygiene before email campaigns, fraud screening at signup, or CRM data audits. Prefer it over single-address checkers when processing batches of 2–100 emails to minimize round-trips. If you need confirmed mailbox existence rather than just DNS validity, enable smtp_check, but be aware that SMTP probes are throttled and never retried.

## Known failure modes

- Submitting an empty array or more than 100 addresses will be rejected by the schema
- SMTP checks are heavily throttled and only attempted once — a failed probe may leave verdict as unknown rather than confirmed
- DNS-only checks cannot confirm mailbox existence, leaving routable addresses with an 'unknown' verdict if smtp_check is false
- Payment failure or insufficient USDC balance will block the request
- Temporary DNS failures may cause valid addresses to appear unresolvable

## How this service works

Check up to 100 email addresses in one paid call, billed per address.

## Output

Returns a verification verdict for each submitted email address, indicating whether it is valid, invalid, or unknown (the last occurring when no SMTP check is performed on a routable address). Results reflect DNS-based and blocklist checks; when smtp_check is enabled, an additional live SMTP probe is attempted once per address to confirm mailbox existence.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "emails": {
   "type": "array",
   "items": {
    "type": "string"
   },
   "maxItems": 100,
   "minItems": 1,
   "description": "Between 1 and 100 addresses. Billed at 0.0006 USDC per address with a 0.001 USDC minimum charge."
  },
  "smtp_check": {
   "type": "boolean",
   "default": false,
   "description": "Ask for an optional SMTP probe. Off by default, heavily throttled, one attempt per target and never retried. Without it the verdict of a routable address stays \"unknown\"."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-email-check-batch-email-verification-ecdfc35a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mailcheck.netzhandwerker.de](https://www.zero.xyz/host/mailcheck.netzhandwerker.de/llms.txt)