# does-site-use-substack

> does-site-use-substack is a paid API for AI agents from site.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-15).

Detects whether a given website uses Substack by fetching its homepage and matching Substack-specific fingerprints in the HTML and response headers.

## Facts

- Endpoint: GET https://site.intel.rallylive.ca/site/uses/substack?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/does-site-use-substack-e045cb23
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Y_zFJO6NCgSUnCKsZNhFX

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-substack-e045cb23
```

Example prompt: Can you check if stratechery.com is running on Substack? I want to know if they use it for publishing before I reach out to pitch a migration.

## When to prefer this

Use this endpoint when you need a lightweight, low-cost ($0.01) single-domain check specifically for Substack usage, as part of sales prospecting, competitor research, or migration planning workflows. Prefer the sibling bulk endpoint if checking more than a few domains at once. Choose this over generic scraping tools when you need a pre-built, reliable fingerprint match specifically for Substack rather than a full technographic suite.

## Known failure modes

- Domain is unreachable or returns a non-200 status — check may return an error or inconclusive result
- Website uses heavy JavaScript rendering so the static homepage fetch misses Substack signals — false negative possible
- Domain redirects to a subdomain or CDN that strips Substack headers — fingerprint match may fail
- Rate limiting or bot-protection on the target site blocks the fetch — may return an error

## How this service works

Does a website use Substack? Fetches the page (homepage for a bare domain) and matches Substack's fingerprints in the HTML and response headers, returning yes/no with the evidence snippet and the category (publishing). 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 target website uses Substack, along with an evidence snippet (matching HTML or header content that triggered the fingerprint) and the technology category label ('publishing').

## 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-substack-e045cb23/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)