# Certificate Transparency Lookup

> Certificate Transparency Lookup is a paid API for AI agents from dev-utils.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-02).

Retrieves Certificate Transparency log data for a domain, including recent certs, certificate issuers, and all subdomains observed via Cert Spotter.

## Facts

- Endpoint: GET https://dev-utils.x402tookit.com/cert-transparency?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/certificate-transparency-lookup-5f41d984
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MRfqUx-1muwYQHh8dk3tX

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 certificate-transparency-lookup-5f41d984
```

Example prompt: Can you pull the certificate transparency log data for stripe.com — I want to see recent certs, who issued them, and all the subdomains that have shown up in CT logs?

## When to prefer this

Use this endpoint when you need passive, non-intrusive subdomain enumeration or certificate audit data sourced from public CT logs — no active scanning or DNS queries are performed. Prefer this over DNS brute-forcing or active scanners when stealth or read-only reconnaissance is required, or when you need historical issuer data and revocation status rather than current DNS resolution.

## Known failure modes

- Domain not found in CT logs returns empty arrays and null fields
- Invalid domain format (includes scheme or path) returns a validation error
- CT log upstream (Cert Spotter) unavailable may return degraded:true with partial data
- Rate limiting or upstream timeout may result in incomplete results
- Very new domains with no certificates return empty/null cert lists

## How this service works

Certificates in Certificate Transparency logs for a domain: recent certs, issuers, subdomains seen (Cert Spotter).

## Output

Returns a structured object containing: the domain queried, a summary verdict, a list of recent certificates (each with ID, issuer, notBefore/notAfter dates, revocation status, and name count), a deduplicated list of certificate issuers with counts, all DNS names seen across certificates (namesSeen), wildcard names, total names count, revoked certificate count, a source URL to the raw Cert Spotter data, and optional disclaimer or degraded-service flags.

## 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",
     "required": [
      "domain"
     ],
     "properties": {
      "domain": {
       "type": "string",
       "description": "Registrable domain such as example.org (no scheme, no path)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "domain": {
       "type": [
        "null",
        "string"
       ]
      },
      "newest": {
       "type": [
        "null",
        "object"
       ],
       "properties": {
        "id": {
         "type": [
          "null",
          "string"
         ]
        },
        "issuer": {
         "type": [
          "null",
          "string"
         ]
        },
        "revoked": {
         "type": [
          "boolean",
          "null"
         ]
        },
        "notAfter": {
         "type": [
          "null",
          "string"
         ]
        },
        "nameCount": {
         "type": [
          "null",
          "number"
         ]
        },
        "notBefore": {
         "type": [
          "null",
          "string"
         ]
        }
       }
      },
      "recent": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "id": {
          "type": [
           "null",
           "string"
          ]
         },
         "issuer": {
          "type": [
           "null",
           "string"
          ]
         },
         "revoked": {
          "type": [
           "boolean",
           "null"
          ]
         },
         "notAfter": {
          "type": [
           "null",
           "string"
          ]
         },
         "nameCount": {
          "type": [
           "null",
           "number"
          ]
         },
         "notBefore": {
          "type": [
           "null",
           "string"
   
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/certificate-transparency-lookup-5f41d984/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dev-utils.x402tookit.com](https://www.zero.xyz/host/dev-utils.x402tookit.com/llms.txt)