# does-site-use-clerk

> does-site-use-clerk is a paid API for AI agents from site.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-11).

Detects whether a given website uses the Clerk authentication platform by fingerprinting its homepage HTML and response headers

## Facts

- Endpoint: GET https://site.intel.rallylive.ca/site/uses/clerk?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/does-site-use-clerk-daa57f79
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UVp4zH7hs1b9-ZKDdHgnO

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 does-site-use-clerk-daa57f79
```

Example prompt: Can you check if stripe.com uses Clerk for authentication? I want to know if they're a Clerk customer before I reach out about a migration.

## When to prefer this

Choose this endpoint when you need a fast, cheap, single-domain technographic check specifically for Clerk authentication. It is purpose-built for sales prospecting, competitor stack analysis, and migration targeting workflows where you need yes/no Clerk detection with evidence. Use bulk sibling endpoints when checking multiple domains. Prefer this over generic web scraping when the sole question is 'does this site use Clerk?'

## Known failure modes

- Domain is unreachable or returns a non-200 response — result may be indeterminate
- Clerk fingerprints are obfuscated or loaded via deferred JavaScript — may return false negative
- Bare domain redirects to a subdomain that uses Clerk — may miss detection if homepage is not the auth entry point
- Rate limiting or bot blocking on target domain — fetch may fail

## How this service works

Does a website use Clerk? Fetches the page (homepage for a bare domain) and matches Clerk's fingerprints in the HTML and response headers, returning yes/no with the evidence snippet and the category (auth). Technographics for sales, competitor research and migration planning, one technology per call. $0.01 per check.

## Output

Returns a yes/no boolean indicating whether the site uses Clerk, along with an evidence snippet (the matching HTML or header fragment that triggered the fingerprint) and the technology category label (auth). Priced at $0.01 per call.

## 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",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/does-site-use-clerk-daa57f79/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from site.intel.rallylive.ca](https://www.zero.xyz/host/site.intel.rallylive.ca/llms.txt)