# SiteCheck PageSpeed Insights

> SiteCheck PageSpeed Insights is a paid API for AI agents from api.sitecheck-api.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-16).

Runs a Google PageSpeed Insights / Lighthouse audit on a public URL and returns performance scores, Core Web Vitals, and optimization opportunities

## Facts

- Endpoint: GET https://api.sitecheck-api.workers.dev/api/pagespeed?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-pagespeed-insights-f3c3ddef
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_bdIoQKnJhPEijeHlWfR1v

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 sitecheck-pagespeed-insights-f3c3ddef
```

Example prompt: Can you run a PageSpeed audit on https://mystore.com/ for mobile and tell me the performance score, LCP, CLS, and what the biggest opportunities are to speed it up?

## When to prefer this

Use this endpoint when you need a real Lighthouse lab run with Core Web Vitals (LCP, CLS, FCP, TBT, SI) and actionable optimization opportunities for a public URL. Prefer it over generic HTTP checkers when you need Google's PageSpeed score specifically, want CrUX field data when available, or need to compare mobile vs. desktop performance with estimated savings per opportunity.

## Known failure modes

- URL is not publicly accessible or returns a non-200 status — audit may fail or return incomplete data
- Private/intranet URLs that Lighthouse cannot reach
- Very slow pages may time out during the lab run
- Invalid URL format causes a 400-level error
- categories or strategy values outside allowed enums may be rejected

## How this service works

Google PageSpeed Insights for one public URL: the Lighthouse scores (performance, seo, accessibility, best-practices), the lab Core Web Vitals (FCP, LCP, CLS, TBT, Speed Index), the CrUX field data when Google has it (LCP, INP, CLS), and the top five opportunities with estimated savings. Mobile by default. A run takes 10 to 40 seconds and is cached for an hour. Keyless calls share Google's quota, so a busy moment is a 503.

## Output

Returns a JSON object with the audited URL, strategy used, timestamp, overall category scores (e.g. performance: 96), lab metrics for LCP, CLS, FCP, TBT, and Speed Index with human-readable display values, optional CrUX field data, a list of improvement opportunities with estimated time/byte savings, and the Lighthouse version used.

## 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",
       "description": "http or https URL of a public page, e.g. https://example.com/"
      },
      "strategy": {
       "type": "string",
       "description": "mobile (default) or desktop"
      },
      "categories": {
       "type": "string",
       "description": "performance (default), seo, accessibility, best-practices; comma-separated"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "url": "https://example.com/",
  "source": "Google PageSpeed Insights v5 (Lighthouse lab run; CrUX field data when available)",
  "finalUrl": "https://example.com/",
  "strategy": "mobile",
  "checkedAt": "2026-10-15T06:00:00.000Z",
  "fieldData": null,
  "categories": {
   "performance": 96
  },
  "labMetrics": {
   "si": {
    "value": 1400,
    "display": "1.4 s"
   },
   "cls": {
    "value": 0,
    "display": "0"
   },
   "fcp": {
    "value": 1100,
    "display": "1.1 s"
   },
   "lcp": {
    "value": 1500,
    "display": "1.5 s"
   },
   "tbt": {
    "value": 0,
    "display": "0 ms"
   }
  },
  "measuredAt": "2026-10-15T06:00:00.000Z",
  "opportunities": [
   {
    "id": "render-blocking-resources",
    "title": "Eliminate render-blocking resources",
    "estimatedSavingsMs": 150,
    "estimatedSavingsBytes": null
   }
  ],
  "lighthouseVersion": "12.0.0"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sitecheck-pagespeed-insights-f3c3ddef/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.sitecheck-api.workers.dev](https://www.zero.xyz/host/api.sitecheck-api.workers.dev/llms.txt)