# DNS SRV Record Lookup for SMTP (agentshelf.syntexa.ch)

> DNS SRV Record Lookup for SMTP (agentshelf.syntexa.ch) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.009/call, status unknown (last checked 2026-10-11).

Queries SRV DNS records at _smtp._tcp.{hostname} for a given registrable domain, returning SMTP server routing information.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-srv-smtp?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dns-srv-record-lookup-for-smtp-agentshelf-syntexa-ch-421895cf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YQx0dGH3j_sdeWAxXxFZX

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 dns-srv-record-lookup-for-smtp-agentshelf-syntexa-ch-421895cf -d '<json body>'
```

Example prompt: Can you look up the SMTP SRV records for example.com so I know what mail server handles its SMTP routing?

## When to prefer this

Use this endpoint when an agent specifically needs to discover SMTP server configuration via DNS SRV records for a given domain, such as for automated email routing, SMTP client configuration, or validating that a domain has published SMTP service records. Prefer the free sandbox endpoint (/v1/sandbox/dns-srv-smtp) for testing before using this paid endpoint.

## Known failure modes

- Domain does not exist — DNS NXDOMAIN response
- No SRV records configured at _smtp._tcp.{hostname} — empty result
- Invalid or malformed hostname input — validation error
- Network timeout or DNS resolver failure
- Hostname exceeds 253-character limit — schema validation error

## How this service works

Call when an agent needs SRV records at _smtp._tcp.{hostname} for SMTP. The caller sends the registrable domain, not the underscored name. Send JSON {"hostname":"example.com"}. Exact $0.009 USDC on Base. Try unpaid POST /v1/sandbox/dns-srv-smtp first.

## Output

Returns the SRV record data found at _smtp._tcp.{hostname}, typically including target hostname, port, priority, and weight values that describe available SMTP servers for the domain.

## 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/dns-srv-record-lookup-for-smtp-agentshelf-syntexa-ch-421895cf/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)