# DKIM Selector k3 Lookup

> DKIM Selector k3 Lookup is a paid API for AI agents from dns.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-20).

Looks up and parses the DKIM public key for the 'k3' selector of a given domain via Cloudflare DoH, returning key type, length, testing flag, and revocation status.

## Facts

- Endpoint: GET https://dns.intel.rallylive.ca/dns/dkim/k3?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dkim-selector-k3-lookup-3f4c89db
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DeslatF0Dj5zt6EvANXaD

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 dkim-selector-k3-lookup-3f4c89db
```

Example prompt: Can you check if the DKIM k3 selector is properly set up for example.com — I want to know the key type, length, whether it's in testing mode, and if the key is revoked?

## When to prefer this

Use this endpoint when you specifically need to inspect the DKIM 'k3' selector for a domain — for example when auditing email authentication configuration, verifying a third-party sender's signing setup, or troubleshooting DKIM failures tied to the k3 selector. Prefer this over generic DNS TXT lookups when you need structured DKIM field parsing (key type, length, revocation status) rather than raw TXT record text.

## Known failure modes

- Domain has no k3._domainkey TXT record — returns NXDOMAIN or empty result
- DNS query fails due to Cloudflare DoH unavailability
- Malformed TXT record that cannot be parsed into DKIM fields
- Domain does not exist — DNS resolution fails
- Rate limiting or payment failure for $0.01 per-call fee

## How this service works

DKIM public key for selector "k3" of a domain: looks up k3._domainkey.<domain> (TXT, Cloudflare DoH) and parses v=, k=, key type, public-key length, testing flag and whether the key is revoked (empty p=). Confirms that mail signed with the k3 selector will verify. $0.01 per lookup.

## Output

Returns parsed DKIM TXT record fields for k3._domainkey.<domain>: version tag (v=), key type (k=), public key length in bits, whether the key is in testing mode, and whether the key is revoked (empty p= field). Confirms whether mail signed with the k3 selector will successfully verify.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dkim-selector-k3-lookup-3f4c89db/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dns.intel.rallylive.ca](https://www.zero.xyz/host/dns.intel.rallylive.ca/llms.txt)