B402 Bazaar Extension

B402 Bazaar is an opt-in discovery extension for paid APIs and resources. A merchant can attach machine-readable metadata to an x402 V2 payment payload. After a successful settlement, B402 stores the metadata so it can be indexed by the B402 Bazaar service.

The extension does not change payment verification or settlement. If it is absent, the payment flow works normally.

Add the Extension

Place the metadata under paymentPayload.extensions.bazaar in the V2 Settle request. You may reuse the same payload for Verify, but only a successful Settle stores metadata for indexing:

Code
{
  "body": {
    "x402Version": 2,
    "paymentPayload": {
      "x402Version": 2,
      "resource": {
        "url": "https://merchant.example.com/v1/weather/singapore",
        "description": "Paid weather forecast",
        "mimeType": "application/json"
      },
      "accepted": {},
      "payload": {},
      "extensions": {
        "bazaar": {
          "description": "Hourly weather forecast by city",
          "routeTemplate": "/v1/weather/:city",
          "info": {
            "input": {
              "type": "http",
              "method": "GET",
              "pathParams": {
                "city": "singapore"
              }
            }
          },
          "schema": {
            "$schema": "https://json-schema.org/draft/2020-12/schema",
            "type": "object",
            "properties": {
              "input": {
                "type": "object",
                "properties": {
                  "type": {
                    "const": "http"
                  },
                  "method": {
                    "enum": ["GET"]
                  }
                },
                "required": ["type", "method"]
              }
            },
            "required": ["input"]
          }
        }
      }
    },
    "paymentRequirements": {}
  }
}

Fields

Unknown extension fields are ignored by B402. Keep metadata free of API keys, secrets, personal data, signatures, and other confidential values.

Publication Behavior

• Metadata is recorded only after a successful V2 settlement.
• The resource URL comes from paymentPayload.resource.url.
• Repeated successful settlements update the listing for the same merchant and resource.
• Missing or invalid info, schema, or info.input.type prevents the metadata from being indexed, even though the payment itself may still settle successfully.
• Invalid Bazaar metadata does not grant payment validity; Verify and Settle still enforce all normal x402 requirements.