# PapaCasper JSON-LD Schema Validator

> PapaCasper JSON-LD Schema Validator is a paid API for AI agents from papacasper.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Validates the JSON-LD structured data markup on a given URL and reports errors, warnings, and schema compliance issues

## Facts

- Endpoint: POST https://papacasper.com/mcp/pay/json_ld_schema_validator
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/papacasper-json-ld-schema-validator-1c04065f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zQfwZFCeK9FteFwv_XDoa

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 papacasper-json-ld-schema-validator-1c04065f -d '<json body>'
```

Example prompt: Can you check if my website at https://example.com/product has valid JSON-LD structured data and let me know about any errors or warnings?

## When to prefer this

Choose this endpoint when you specifically need to validate JSON-LD structured data markup on a webpage for SEO or schema.org compliance purposes. It is ideal for technical SEO audits, pre-launch QA, or debugging why rich snippets are not appearing in search results. Prefer this over generic SEO audit tools when the specific concern is structured data correctness rather than page speed, backlinks, or content quality.

## Known failure modes

- URL is unreachable or returns a non-200 status — validation cannot proceed
- Target page has no JSON-LD at all — returns empty or no-schema result
- Malformed URL input — returns a validation or parsing error
- Page behind authentication or bot protection — content not accessible
- Timeout on slow-loading pages
- JSON-LD present but embedded in a way that is not parseable — partial results

## How this service works

A hosted MCP server exposing utility tools any AI agent can call over HTTP — page-to-markdown, SEO audits, robots/sitemap checks, and more.

## Output

Returns a structured object indicating whether the JSON-LD on the target URL is valid, along with any detected errors, warnings, and information about the schema types found (e.g. Product, Article, Organization). May include field-level details about what is missing or malformed.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "url"
 ],
 "properties": {
  "url": {
   "type": "string",
   "description": "The URL to check"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/papacasper-json-ld-schema-validator-1c04065f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from papacasper.com](https://www.zero.xyz/host/papacasper.com/llms.txt)