# Certificate Transparency Log Lookup

> Certificate Transparency Log Lookup is a paid API for AI agents from netintel-production-440c.up.railway.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-09).

Queries crt.sh certificate transparency logs to enumerate all SSL certificates issued for a domain, returning subdomains, issuers, validity periods, and a risk score.

## Facts

- Endpoint: GET https://netintel-production-440c.up.railway.app/cert-transparency/lookup?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-09
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/netintel-production-440c-up-railway-app-139e1230
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zbPOlc_dPBA9S_NtD4qud

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 netintel-production-440c-up-railway-app-139e1230
```

Example prompt: Look up all SSL certificates ever issued for example.com in the certificate transparency logs — include subdomains, flag any wildcard certs or ones expiring within 30 days, and give me a risk score.

## When to prefer this

Use this endpoint when you need passive, read-only reconnaissance on a domain's SSL certificate history without touching the target — ideal for subdomain discovery, security audits, certificate expiry monitoring, or detecting unauthorized certificate issuances. Prefer over active port scanners when stealth and non-intrusiveness matter.

## Known failure modes

- Invalid or malformed domain name returns validation error
- Domain with no certificates in crt.sh returns empty results with zero count
- Limit exceeding 500 returns error or is clamped
- crt.sh upstream unavailability causes timeout or 502 error
- Rate limiting may occur for high-frequency queries

## How this service works

Query the crt.sh certificate transparency log database to enumerate all SSL certificates ever issued for a domain — returns subdomains discovered, certificate issuers, validity periods, and a risk score flagging wildcard certs, expiring certs, and suspicious issuance patterns.

## Output

Returns a list of certificates with issuer details and validity periods, an array of unique subdomains discovered, wildcard certificates, recently issued certificates, certificates expiring within 30 days, a numeric risk score, a letter grade, and findings describing suspicious or notable patterns.

## 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": {
      "limit": {
       "type": "number",
       "description": "Maximum number of certificates to return (default: 100, max: 500)"
      },
      "domain": {
       "type": "string",
       "description": "Domain name to query certificate transparency logs for (e.g. example.com)"
      },
      "include_subdomains": {
       "type": "boolean",
       "description": "Whether to include subdomain certificates (default: true)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "certs": {
       "type": "array"
      },
      "grade": {
       "type": "string"
      },
      "score": {
       "type": "number"
      },
      "domain": {
       "type": "string"
      },
      "issuers": {
       "type": "array"
      },
      "findings": {
       "type": "array"
      },
      "wildcard_certs": {
       "type": "array"
      },
      "recently_issued": {
       "type": "array"
      },
      "total_certs_found": {
       "type": "number"
      },
      "unique_subdomains": {
       "type": "array"
      },
      "unique_subdomain_count": {
       "type": "number"
      },
      "expiring_within_30_days": {
       "type": "array"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "certs": [
   {
    "id": 12345678,
    "sans": [
     "example.com",
     "www.example.com"
    ],
    "issuer": "Let's Encrypt",
    "not_after": "2024-04-01T00:00:00Z",
    "is_expired": false,
    "not_before": "2024-01-01T00:00:00Z",
    "common_name": "example.com",
    "is_wildcard": false,
    "days_until_expiry": 90
   }
  ],
  "grade": "A",
  "score": 100,
  "domain": "example.com",
  "issuers": [
   "Let's Encrypt"
  ],
  "findings": [],
  "wildcard_certs": [],
  "recently_issued": [],
  "total_certs_found": 47,
  "unique_subdomains": [
   "www.example.com",
   "mail.example.com"
  ],
  "unique_subdomain_count": 2,
  "expiring_within_30_days": []
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/netintel-production-440c-up-railway-app-139e1230/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from netintel-production-440c.up.railway.app](https://www.zero.xyz/host/netintel-production-440c.up.railway.app/llms.txt)