# X402 Web Extraction - Structured Field Extractor

> X402 Web Extraction - Structured Field Extractor is a paid API for AI agents from x402.feld-feder.at, paid per call via x402, $0.01/call, status down (last checked 2026-10-22).

Extracts structured data fields from a web page URL using CSS or XPath selectors, returning named field values as arrays of strings.

## Facts

- Endpoint: POST https://x402.feld-feder.at/v1/web/extract?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-web-extraction-structured-field-extractor-e04f82ab
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QFQcG5kGTy6JQolhlfs3x

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 x402-web-extraction-structured-field-extractor-e04f82ab -d '<json body>'
```

Example prompt: Go to https://news.ycombinator.com and extract the top story titles and their point scores using CSS selectors — '.titleline > a' for titles and '.score' for points — and return them as named fields 'title' and 'score'.

## When to prefer this

Choose this endpoint when you need to extract specific named fields from a known web page URL using precise CSS or XPath selectors, and you want structured, machine-readable output per field. Prefer this over general web search when you already know the page URL and the DOM structure. Best for structured scraping tasks where selector-based extraction is reliable (static HTML pages). Not suitable for JavaScript-heavy SPAs or full-page crawling.

## Known failure modes

- URL unreachable or returns non-200 status — field values may be empty or error returned
- Selector matches no elements — field returned with empty 'values' array
- Malformed CSS or XPath selector — request rejected with validation error
- URL exceeds 4096 character limit — request rejected
- More than 100 fields requested — request rejected
- Payment of $0.01 USDC not provided or rejected — 402 Payment Required response
- Webpage requires JavaScript rendering — static extractor may miss dynamically loaded content

## How this service works

Pay-per-request data tools for AI agents.

## Output

A JSON object with an 'ok' boolean and a 'data' object containing a 'fields' array. Each element in the array has a 'name' (matching the requested field name) and a 'values' array of strings containing all matched content for that selector. May also include cache metadata indicating whether the result was served from cache and its age.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "title": "WebExtractRequest",
     "required": [
      "url",
      "fields"
     ],
     "properties": {
      "url": {
       "type": "string",
       "title": "Url",
       "maxLength": 4096,
       "minLength": 1
      },
      "fields": {
       "type": "array",
       "items": {
        "type": "object",
        "title": "ExtractionFieldRequest",
        "required": [
         "name",
         "selector_type",
         "selector"
        ],
        "properties": {
         "name": {
          "type": "string",
          "title": "Name",
          "maxLength": 64,
          "minLength": 1
         },
         "selector": {
          "type": "string",
          "title": "Selector",
          "maxLength": 8192,
          "minLength": 1
         },
         "selector_type": {
          "enum": [
           "css",
           "xpath"
          ],
          "type": "string",
          "title": "Selector Type"
         }
        },
        "additionalProperties": false
       },
       "title": "Fields",
       "maxItems": 100,
       "minItems": 1
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "ResponseEnvelope[StructuredExtractionResult]",
     "required": [
      "data"
     ],
     "properties": {
      "ok": {
       "type": "boolean",
       "const": true,
       "title": "Ok",
       "default": true
      },
      "data": {
       "type": "object",
       "title": "StructuredExtractionResult",
       "required": [
        "fields"
       ],
       "properties": {
        "fields": {
         "type": "array",
         "items": {
          "type": "object",
          "title": "StructuredFieldResult",
          "required": [
           "name",
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "data": {
   "fields": []
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-web-extraction-structured-field-extractor-e04f82ab/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.feld-feder.at](https://www.zero.xyz/host/x402.feld-feder.at/llms.txt)