# ProbeKit DKIM Public Key Validator

> ProbeKit DKIM Public Key Validator is a paid API for AI agents from api.probekit.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-30).

Fetches and validates the DKIM public key DNS record for a given domain and selector, checking key type, size, revocation status, and syntax.

## Facts

- Endpoint: GET https://api.probekit.dev/v1/mail/dkim?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/probekit-dkim-public-key-validator-8b7b68b0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FKtdUfF4EALutgSpU7yvr

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 probekit-dkim-public-key-validator-8b7b68b0
```

Example prompt: Can you check if the DKIM key for selector 'google' on domain 'acme.com' is properly published in DNS and not revoked?

## When to prefer this

Use this endpoint when you have a specific DKIM selector (from an email's DKIM-Signature header or known configuration) and need to confirm the public key is correctly published, has adequate key size, and has not been revoked. Prefer this over the broad DKIM selector discovery endpoint when you already know the selector. This does not verify message signatures — use it purely for DNS key record inspection and validation.

## Known failure modes

- Domain or selector not found in DNS — record does not exist
- Malformed domain or selector input — validation error returned
- DKIM record found but key is revoked (empty p= field)
- DNS lookup timeout or resolver failure
- Selector exists but record has syntax errors preventing parsing

## How this service works

Fetch and validate the DKIM public key record at selector._domainkey for a domain: key type, key size, revocation and syntax, with coded findings. Use when an agent knows the selector (s= in a DKIM-Signature header) and must confirm that the key is published and usable. It does not verify message signatures.

## Output

Returns the parsed DKIM TXT record for the specified selector._domainkey.<domain>, including key type (e.g. RSA), key size in bits, whether the key is revoked (p= empty), syntax validity, and coded findings describing any issues or confirmations about the record's usability.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "title": "DkimInput",
     "required": [
      "domain",
      "selector"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "title": "Domain",
       "examples": [
        "example.com"
       ],
       "maxLength": 1024,
       "minLength": 1
      },
      "selector": {
       "type": "string",
       "title": "Selector",
       "examples": [
        "selector1"
       ],
       "maxLength": 200,
       "minLength": 1
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/probekit-dkim-public-key-validator-8b7b68b0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.probekit.dev](https://www.zero.xyz/host/api.probekit.dev/llms.txt)