# agent402.tools TLS Certificate Inspector

> agent402.tools TLS Certificate Inspector is a paid API for AI agents from agent402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Fetches and returns the TLS certificate details of any public hostname, including subject, issuer, validity window, days remaining, SANs, and SHA-256 fingerprint.

## Facts

- Endpoint: POST https://agent402.tools/api/tls-cert
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-tools-tls-certificate-inspector-dccfa1d5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_X-7hOMHfROJKSQ5ELgreC

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 agent402-tools-tls-certificate-inspector-dccfa1d5 -d '<json body>'
```

Example prompt: What does the TLS certificate look like for api.stripe.com — I want to know the issuer, how many days it has left, its SANs, and the SHA-256 fingerprint.

## When to prefer this

Use this endpoint when you need to programmatically inspect a live TLS certificate for any public HTTPS host — especially to check expiry dates, verify issuers, retrieve SANs for coverage validation, or obtain a SHA-256 fingerprint for certificate pinning or security audits. Prefer this over manual browser inspection or openssl CLI when automation or agent-driven workflows are needed.

## Known failure modes

- Host not reachable or does not support TLS — returns connection error
- Invalid or malformed hostname — returns validation error
- Certificate chain is broken or self-signed in unexpected way — may return partial data or error
- Port 443 not open on the specified host — returns timeout or connection refused
- Host field missing from request body — returns 400 bad request

## How this service works

Inspect the TLS certificate of any public host: subject, issuer, validity window, days remaining, SANs, and SHA-256 fingerprint.

## Output

Returns structured details about the host's TLS certificate: subject common name, issuer organization, validity start and expiry dates, days remaining until expiry, the list of Subject Alternative Names (SANs), and the SHA-256 fingerprint of the certificate.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "host": {
   "type": "string",
   "description": "Hostname (port 443)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "host": "example.com",
  "issuer": "DigiCert",
  "validTo": "2027-01-01T00:00:00.000Z",
  "altNames": [
   "example.com"
  ],
  "daysRemaining": 204
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-tools-tls-certificate-inspector-dccfa1d5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.tools](https://www.zero.xyz/host/agent402.tools/llms.txt)