Marketplace · API · x402

market.561.group/v1/book-record

Validate one ISBN checksum and return its Open Library edition, work and author records projected into one sourced CSL-JSON book item; invalid or absent ISBNs return an explicit refusal. The FOUR truth reading is true when found and neither on refusal.

Endpoint	`https://market.561.group/v1/book-record`
Trust	100% uptime over 1 checks · ~1088 ms
Pricing	Pay per call with x402, no account. Call it to get an exact quote before paying.
network	eip155:8453
scheme	exact
pay to	0x32886F6F361C1d570255c2762967A2e41D0E9B1a
method	POST
last updated	2026-10-24T13:18:40.46Z

Use it

Call it (an x402 client pays automatically)

curl -i https://market.561.group/v1/book-record
# 402 reply -> sign PAYMENT-REQUIRED with an x402 client (e.g. @x402/fetch) -> retry with PAYMENT-SIGNATURE

This listing as JSON

curl https://aipaygen.com/v1/catalog/api/x402-aa0fe39132074f0e

Search the whole marketplace from your agent (MCP)

{
  "mcpServers": {
    "aipaygen": {
      "url": "https://aipaygen.com/mcp"
    }
  }
}