# HALOWERK buerowerk – Email Domain Underscore Review

> HALOWERK buerowerk – Email Domain Underscore Review is a paid API for AI agents from buero.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-18).

Analyzes a list of email addresses to review and flag those containing underscores in the domain part.

## Facts

- Endpoint: POST https://buero.halowerk.com/v1/baumarkt/mail/domain-underscore-review?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/halowerk-buerowerk-email-domain-underscore-review-6e527400
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wdnV6rWTcvhr4BjuctfAL

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 halowerk-buerowerk-email-domain-underscore-review-6e527400 -d '<json body>'
```

Example prompt: Can you review this list of email addresses and flag any that have underscores in their domain part? Here are the emails: user@some_domain.com, hello@example.com, test@my_company.org.

## When to prefer this

Choose this endpoint when you need to programmatically audit or clean a batch of email addresses specifically for underscore characters in the domain part — particularly useful for CRM hygiene, mailing list validation, or B2B outreach preparation where non-standard domain formats can cause deliverability issues. Prefer this over generic email validation services when underscore-in-domain detection is the primary concern.

## Known failure modes

- Empty or missing emails array returns a validation error
- Emails array exceeds 500 items results in rejection
- Invalid email format strings may be flagged or cause processing errors
- Malformed request body returns a 400 error
- Payment not provided or insufficient USDC results in 402 Payment Required

## How this service works

HALOWERK buerowerk — bezahlte Endpunkte nach x402. Preise in USDC auf Base Mainnet.

## Output

A JSON response indicating which of the submitted email addresses have underscores in their domain segment, likely including a list of flagged emails, their domain portions, and a summary of findings per address or overall.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "emails": {
   "type": "array",
   "items": {
    "type": "string",
    "maxLength": 320,
    "minLength": 1
   },
   "maxItems": 500,
   "minItems": 1
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/halowerk-buerowerk-email-domain-underscore-review-6e527400/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from buero.halowerk.com](https://www.zero.xyz/host/buero.halowerk.com/llms.txt)