# Tech Detect — Pay-Per-Call Technology Stack Detection

> Tech Detect — Pay-Per-Call Technology Stack Detection is a paid API for AI agents from stack.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-12).

Detects the full technology stack of a given domain/URL, returning each detected technology with confidence scores and evidence, billed per call in USDC via x402.

## Facts

- Endpoint: POST https://stack.halowerk.com/stack/articles/paypal?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tech-detect-pay-per-call-technology-stack-detection-17f4ce3f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Yy4pt9sC-u-ElyVbkD7M1

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 tech-detect-pay-per-call-technology-stack-detection-17f4ce3f -d '<json body>'
```

Example prompt: What technologies is paypal.com running? I want confidence scores and evidence for each hit — detect the full tech stack for that domain.

## When to prefer this

Choose this endpoint when you need per-call, no-signup technology detection with crypto micropayments via x402. It is ideal for agents that need on-demand stack fingerprinting without managing API keys or subscriptions. The optional 'previous' parameter makes it especially strong for change-detection workflows where you want to diff the current stack against a prior observation.

## Known failure modes

- URL is unreachable or returns non-200 status — detection may be incomplete or return empty results
- Domain uses heavy bot protection (e.g. Cloudflare challenge) — fingerprinting may be blocked
- Private or internal URLs not accessible from the scanner — returns no data
- Malformed URL input — validation error returned
- x402 payment failure — call not processed, no results returned

## How this service works

Domain in, technology stack out. Confidence and evidence for every hit. Pay per call in USDC over x402. No signup, no API key.

## Output

Returns a structured list of detected technologies for the given domain, each entry including the technology name, category (e.g. CMS, CDN, JavaScript framework), version where detectable, confidence score, and supporting evidence. Covers frontend frameworks, backend technologies, analytics platforms, hosting providers, and more.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "maxLength": 2048
  },
  "previous": {
   "type": "object",
   "required": [
    "observed_at",
    "technologies"
   ],
   "properties": {
    "observed_at": {
     "type": "string",
     "maxLength": 40
    },
    "technologies": {
     "type": "array",
     "items": {
      "type": "object",
      "required": [
       "name",
       "category",
       "version"
      ],
      "properties": {
       "name": {
        "type": "string",
        "maxLength": 150
       },
       "version": {
        "type": [
         "string",
         "null"
        ],
        "maxLength": 80
       },
       "category": {
        "type": "string",
        "maxLength": 80
       }
      },
      "additionalProperties": false
     },
     "maxItems": 150
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tech-detect-pay-per-call-technology-stack-detection-17f4ce3f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stack.halowerk.com](https://www.zero.xyz/host/stack.halowerk.com/llms.txt)