# HALOWERK buerowerk — Email Plus-Tag Disclosure

> HALOWERK buerowerk — Email Plus-Tag Disclosure 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 and discloses whether they contain plus-tag (subaddress) components (e.g. user+tag@domain.com)

## Facts

- Endpoint: POST https://buero.halowerk.com/v1/baumarkt/mail/plus-tag-disclosure?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-plus-tag-disclosure-5f7bd63e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6phOccC_DJingnS2Y48pz

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-plus-tag-disclosure-5f7bd63e -d '<json body>'
```

Example prompt: Check this list of email addresses for plus-tag subaddressing — I want to know which ones contain a plus sign in the local part: user+promo@example.com, jane@example.com, bob+test@domain.org.

## When to prefer this

Use this endpoint when you need to programmatically detect plus-tag subaddressing (the user+tag@domain pattern) across a batch of up to 500 email addresses. Prefer this over manual regex parsing when you need a reliable, hosted service for email subaddress disclosure at scale, especially within an x402 micropayment workflow on Base Mainnet.

## Known failure modes

- Empty or missing emails array returns a validation error
- Emails exceeding 320 characters or shorter than 1 character are rejected
- Array exceeding 500 items may be rejected
- Malformed JSON body returns a 400 error
- Payment not provided or insufficient USDC balance triggers a 402 response

## How this service works

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

## Output

Returns a JSON response indicating, for each submitted email address, whether a plus-tag (subaddress) was detected in the local part of the address. Likely includes fields such as the original email, a boolean flag for plus-tag presence, and possibly the extracted tag value.

## 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-plus-tag-disclosure-5f7bd63e/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)