# agentshelf.syntexa.ch SMTP DKIM TXT Lookup (smtp._domainkey)

> agentshelf.syntexa.ch SMTP DKIM TXT Lookup (smtp._domainkey) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-01).

Looks up the DKIM TXT DNS record at smtp._domainkey.{hostname} and returns its value

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-txt-dkim-smtp?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-syntexa-ch-smtp-dkim-txt-lookup-smtp-domainkey-e5c0bde6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pQevLUD-kO-Wx-3LP_goK

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 agentshelf-syntexa-ch-smtp-dkim-txt-lookup-smtp-domainkey-e5c0bde6 -d '<json body>'
```

Example prompt: Can you look up the DKIM TXT record for the smtp selector on example.com — I need to see what's published at smtp._domainkey.example.com.

## When to prefer this

Use this endpoint when you specifically need the DKIM TXT record for the 'smtp' selector (smtp._domainkey.{hostname}). For other selectors (e.g. google._domainkey or pic._domainkey), use the corresponding sibling endpoints. Prefer the unpaid sandbox version (POST /v1/sandbox/dns-txt-dkim-smtp) when available and only use this paid endpoint when the sandbox is unavailable or not appropriate.

## Known failure modes

- Domain does not exist or has no smtp._domainkey TXT record — returns empty or NXDOMAIN response
- Invalid hostname format — returns validation error
- DNS resolution timeout — returns error indicating lookup failure
- Network or upstream DNS error — returns service error

## How this service works

Call when an agent needs TXT at smtp._domainkey.{hostname}. A different selector is a different DNS name. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/dns-txt-dkim-smtp first.

## Output

The DNS TXT record value published at smtp._domainkey.{hostname}, typically containing the DKIM public key and policy fields (e.g. v=DKIM1; k=rsa; p=...).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "hostname": {
   "type": "string",
   "examples": [
    "example.com"
   ],
   "maxLength": 253,
   "minLength": 1,
   "description": "Public DNS hostname such as example.com. Not a URL, not an IP literal, and not a private name."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-syntexa-ch-smtp-dkim-txt-lookup-smtp-domainkey-e5c0bde6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)