# Northline WebKit – URL Metadata (Link Preview)

> Northline WebKit – URL Metadata (Link Preview) is a paid API for AI agents from northline-webkit.northline-c86.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-31).

Fetches link preview metadata for a given URL, including title, favicon, Open Graph image, and final (post-redirect) URL.

## Facts

- Endpoint: GET https://northline-webkit.northline-c86.workers.dev/v1/url/metadata?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/northline-webkit-url-metadata-link-preview-3743a3ad
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Fc60u4LlKWL02gARSUxgm

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 northline-webkit-url-metadata-link-preview-3743a3ad
```

Example prompt: Can you grab the link preview metadata for https://openai.com — I need the page title, favicon, and Open Graph image to build a rich link card.

## When to prefer this

Choose this endpoint when you need lightweight link preview metadata (title, favicon, OG image, final URL) for a single URL without a heavyweight scrape. Ideal for building link card UIs, enriching feeds, or verifying social preview tags. Prefer this over full-page scrapers when you only need metadata headers, not page content. No API key or signup required — pay per call via USDC on Base.

## Known failure modes

- URL is unreachable or returns non-200 → error or empty metadata
- URL requires authentication or is behind a paywall → partial or missing metadata
- Open Graph tags absent → openGraph fields empty or null
- Invalid or malformed URL input → validation error
- Redirect loop → may fail to resolve finalUrl
- Payment not completed via x402 → 402 Payment Required response

## How this service works

Pay-per-call web and domain utilities for AI agents: URL to Markdown, link preview metadata, links, uptime/redirect check, DNS, email-domain check, WHOIS/RDAP, robots.txt and a one-call domain report. x402 (USDC on Base), no API key, no signup.

## Output

Returns a JSON object containing the page title, favicon URL, final resolved URL (after redirects), and Open Graph metadata such as the og:image URL. Example: {title: 'GitHub', favicon: 'https://github.com/favicon.ico', finalUrl: 'https://github.com/', openGraph: {image: 'https://github.githubassets.com/...'}}

## 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",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "minLength": 3,
       "description": "Public http(s) URL (scheme optional)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "title": "GitHub",
  "favicon": "https://github.com/favicon.ico",
  "finalUrl": "https://github.com/",
  "openGraph": {
   "image": "https://github.githubassets.com/..."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/northline-webkit-url-metadata-link-preview-3743a3ad/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from northline-webkit.northline-c86.workers.dev](https://www.zero.xyz/host/northline-webkit.northline-c86.workers.dev/llms.txt)