# agentshelf.syntexa.ch TLS Certificate Summary (Alt Port 8443)

> agentshelf.syntexa.ch TLS Certificate Summary (Alt Port 8443) is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.007/call, status unknown (last checked 2026-09-29).

Retrieves and summarizes the TLS certificate for a host on TCP port 8443 (not the standard 443), returning key certificate details.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/tls-alt?utm_source=zero.xyz
- Price: $0.007/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-syntexa-ch-tls-certificate-summary-alt-port-8443-d24fa948
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pgUSlXJCm_oVHYezuqTbL

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 agentshelf-syntexa-ch-tls-certificate-summary-alt-port-8443-d24fa948 -d '<json body>'
```

Example prompt: Can you pull the TLS certificate summary for api.example.com on port 8443 and tell me who issued it and when it expires?

## When to prefer this

Use this endpoint specifically when you need TLS certificate information from a host's alternate port 8443 rather than the standard HTTPS port 443. It is ideal for auditing backend services, admin interfaces, or internal APIs that expose TLS on non-standard ports.

## Known failure modes

- Host unreachable or refusing connections on port 8443 — connection timeout or refused error
- Private/reserved IP addresses rejected (SSRF protection) — 4xx error
- Invalid or malformed URL/host input — validation error
- Host presents no valid TLS certificate on port 8443 — TLS handshake failure
- Payment not included or insufficient — 402 Payment Required

## How this service works

Call when an agent needs a certificate summary for TCP 8443, not 443. Exact $0.007 USDC. Prefer unpaid POST /v1/sandbox/tls-alt first.

## Output

Returns a structured certificate summary including the subject, issuer, validity period (not-before, not-after), subject alternative names (SANs), and other key fields from the TLS handshake on port 8443.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048,
   "minLength": 8,
   "description": "Public URL whose hostname is inspected. Provide url or host. Private targets are rejected."
  },
  "host": {
   "type": "string",
   "examples": [
    "example.com"
   ],
   "maxLength": 253,
   "minLength": 1,
   "description": "Public hostname such as example.com. The port and check are fixed by the SKU. Provide host or url."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-syntexa-ch-tls-certificate-summary-alt-port-8443-d24fa948/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)