# DNS SRV PubSub Record Lookup

> DNS SRV PubSub Record Lookup is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.006/call, status unknown (last checked 2026-10-11).

Resolves SRV records at _pubsub._tcp.{hostname} for XMPP pubsub service discovery given a registrable domain name

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/dns-srv-pubsub?utm_source=zero.xyz
- Price: $0.006/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-pubsub-record-lookup-f6444756
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FvtMC_3I4DycFU4VYJt-y

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-pubsub-record-lookup-f6444756 -d '<json body>'
```

Example prompt: Look up the _pubsub._tcp SRV records for the domain jabber.org so I can discover its XMPP pubsub server and port.

## When to prefer this

Use this endpoint when an agent specifically needs to discover XMPP pubsub service endpoints via DNS SRV records (_pubsub._tcp) for a given registrable domain. Prefer the free sandbox endpoint POST /v1/sandbox/dns-srv-pubsub first for testing. Choose this paid endpoint only when a real, authoritative DNS SRV pubsub lookup is required in production at $0.006 USDC per call.

## Known failure modes

- Domain has no _pubsub._tcp SRV records — returns empty result or NXDOMAIN
- Invalid or malformed hostname input — validation error
- DNS resolution timeout or upstream failure — service error
- Hostname exceeds 253-character limit — schema validation error
- Payment not provided or insufficient — 402 Payment Required

## How this service works

Call when an agent needs SRV records at _pubsub._tcp.{hostname} for XMPP pubsub. The caller sends the registrable domain, not the underscored name. Send JSON {"hostname":"example.com"}. Exact $0.006 USDC on Base. Try unpaid POST /v1/sandbox/dns-srv-pubsub first.

## Output

Returns the SRV record(s) found at _pubsub._tcp.{hostname}, including fields such as priority, weight, port, and target hostname for each record, enabling XMPP pubsub service discovery.

## 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-pubsub-record-lookup-f6444756/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)