# UOS Genesis URL Digest (SHA-256 Fingerprint)

> UOS Genesis URL Digest (SHA-256 Fingerprint) is a paid API for AI agents from genesis.palsus2023.workers.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-02).

Fetches a public URL and returns its SHA-256 digest for content integrity verification and change detection.

## Facts

- Endpoint: POST https://genesis.palsus2023.workers.dev/v1/url_digest?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/uos-genesis-url-digest-sha-256-fingerprint-3d855de8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zJOS8RXo3Ypyr5CwB3Snp

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 uos-genesis-url-digest-sha-256-fingerprint-3d855de8 -d '<json body>'
```

Example prompt: Can you fetch https://example.com/data.json and give me its SHA-256 fingerprint so I can verify whether the content changes over time?

## When to prefer this

Choose this endpoint when you need a lightweight, pay-per-use SHA-256 fingerprint of any public HTTP/HTTPS resource without setting up your own infrastructure. Ideal for agents performing periodic integrity checks, tamper detection, or change monitoring on web pages and APIs, especially when operating in an x402 micropayment context on Base USDC.

## Known failure modes

- URL is unreachable or returns a non-200 status — digest may reflect error page content or request may fail
- Private or intranet URLs cannot be fetched by the remote worker
- Payment failure via x402/USDC results in 402 response before any fetch occurs
- Malformed or non-URI input causes validation error
- Very large resources may time out on Cloudflare Worker execution limits

## How this service works

Autonomous paid machine utilities using x402 and Base USDC.

## Output

Returns a JSON object containing the original URL, the SHA-256 hex digest of the fetched content, the HTTP status code of the upstream response, and the algorithm name ('SHA-256').

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "description": "Public HTTP or HTTPS resource to fetch and fingerprint with SHA-256 for integrity verification and change detection."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object"
  }
 },
 "additionalProperties": true
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "url": "https://example.com",
  "digest": "example_sha256_digest",
  "status": 200,
  "algorithm": "SHA-256"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/uos-genesis-url-digest-sha-256-fingerprint-3d855de8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from genesis.palsus2023.workers.dev](https://www.zero.xyz/host/genesis.palsus2023.workers.dev/llms.txt)