> ## Documentation Index
> Fetch the complete documentation index at: https://developers.circle.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Discover x402 services

> One public endpoint to discover x402 services that accept USDC, across many blockchains. No API key, no account.

## Categories

Every listing is classified with one category in `metadata.provider.category`.
Filter on it with the `category` query parameter to narrow results to a domain.

| Category              | Description                                             |
| :-------------------- | :------------------------------------------------------ |
| `SOCIAL_INTELLIGENCE` | Social platform data and audience or sentiment signals. |
| `FINANCIAL_ANALYSIS`  | Market data, prices, and financial analytics.           |
| `WEB_SEARCH_RESEARCH` | Web search, scraping, and research retrieval.           |
| `PREDICTION_MARKETS`  | Odds, forecasts, and prediction-market data.            |
| `CREATIVE`            | Media generation such as images, audio, and text.       |
| `INFRASTRUCTURE`      | Developer tooling and infrastructure utilities.         |

## Paying for a service

Discovery tells you what each service accepts. To actually pay, use one of two
rails:

* **Vanilla x402**: a signed onchain USDC transfer that any USDC wallet,
  including a centralized custodial one, can produce.
* **Circle Gateway**: offchain, batched settlement for gasless, sub-cent
  payments.

Each listing's `accepts[]` and its `supportsVanillax402` and
`supportsCircleGateway` flags tell you which rails it takes. To pay from Circle
CLI, see
[Pay for a service](/agent-stack/agent-nanopayments/operations/pay-for-service).
For the concepts and buyer integration, see
[Agent nanopayments](/agent-stack/agent-nanopayments).

<Tip>
  To find services payable on a specific blockchain, filter with the structured
  `network` parameter, not the `query` text field. `query` matches free text
  (URLs, providers, descriptions, tags), so it does not reliably match a chain.
</Tip>

## Related

* [Service catalog](https://agents.circle.com/services)
* [OpenAPI spec](https://agents.circle.com/.well-known/openapi.json)
* [A2A card](https://agents.circle.com/.well-known/a2a.json)
* [Agent skills index (llms.txt)](https://agents.circle.com/llms.txt)


## OpenAPI

````yaml openapi/agent-marketplace-discovery.yaml get /v2/x402/discovery/resources
openapi: 3.0.3
info:
  title: Agent Marketplace Discovery API
  version: v2
  description: >-
    One public endpoint to discover x402 services that accept USDC across many
    blockchains. No API key, no account.
servers:
  - url: https://api.circle.com
security: []
tags:
  - name: Discovery
    description: Discover x402-compatible services in the Agent Marketplace.
paths:
  /v2/x402/discovery/resources:
    get:
      tags:
        - Discovery
      summary: List marketplace resources
      description: >-
        Returns x402-compatible services that accept USDC across 15+ blockchain
        networks. The catalog is curated and continuously sanctions-screened on
        the seller side. Every listing carries structured payment requirements
        and JSON Schema so any wallet can pay for and call a service on top of
        x402.


        This endpoint is public — no authentication, no API key, and no Circle
        account required. Responses support `gzip` compression; pass
        `--compressed` when calling with curl.
      operationId: listDiscoveryResources
      parameters:
        - name: query
          in: query
          description: >-
            Fuzzy search across resource URLs, providers, descriptions, and
            tags.
          required: false
          schema:
            type: string
            example: weather
        - name: type
          in: query
          description: Protocol type.
          required: false
          schema:
            type: string
            enum:
              - http
              - mcp
            example: http
        - name: category
          in: query
          description: >-
            Service category. One of `SOCIAL_INTELLIGENCE`,
            `FINANCIAL_ANALYSIS`, `WEB_SEARCH_RESEARCH`, `PREDICTION_MARKETS`,
            `CREATIVE`, or `INFRASTRUCTURE`.
          required: false
          schema:
            type: string
            enum:
              - SOCIAL_INTELLIGENCE
              - FINANCIAL_ANALYSIS
              - WEB_SEARCH_RESEARCH
              - PREDICTION_MARKETS
              - CREATIVE
              - INFRASTRUCTURE
            example: FINANCIAL_ANALYSIS
        - name: network
          in: query
          description: >-
            CAIP-2 identifier (for example, `eip155:8453`) or a legacy SDK name
            (for example, `base`, `base-sepolia`). Only EVM chains have legacy
            aliases; Solana must use its full CAIP-2 identifier.
          required: false
          schema:
            type: string
            example: eip155:8453
        - name: asset
          in: query
          description: Payment token contract address.
          required: false
          schema:
            type: string
            example: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
        - name: scheme
          in: query
          description: Payment scheme (for example, `exact`).
          required: false
          schema:
            type: string
            example: exact
        - name: payTo
          in: query
          description: Merchant (seller) wallet address.
          required: false
          schema:
            type: string
            example: '0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed'
        - name: maxUsdPrice
          in: query
          description: Maximum price per request in USD (for example, `0.01`).
          required: false
          schema:
            type: number
            example: 0.01
        - name: supportsVanillax402
          in: query
          description: >-
            When `true`, returns only endpoints that support vanilla x402
            (onchain payments).
          required: false
          schema:
            type: boolean
            example: true
        - name: supportsCircleGateway
          in: query
          description: >-
            When `true`, returns only endpoints that support Circle Gateway
            (offchain, batched payments).
          required: false
          schema:
            type: boolean
            example: true
        - name: siwx
          in: query
          description: >-
            When `true`, returns only SIWX (Sign-In With X, browser-auth)
            endpoints; when `false`, excludes them; omit to return all. Use
            `false` for CLI or automation.
          required: false
          schema:
            type: boolean
            example: false
        - name: fields
          in: query
          description: Comma-separated list of fields to include in each item.
          required: false
          schema:
            type: string
            example: resource,type,metadata.provider.name
        - name: limit
          in: query
          description: Number of items to return. Default `50`, maximum `200`.
          required: false
          schema:
            type: integer
            minimum: 1
            maximum: 200
            default: 50
            example: 50
        - name: offset
          in: query
          description: Number of items to skip, for pagination. Default `0`.
          required: false
          schema:
            type: integer
            minimum: 0
            default: 0
            example: 0
      responses:
        '200':
          description: A paginated list of x402-compatible service listings.
          content:
            application/json:
              schema:
                type: object
                properties:
                  x402Version:
                    type: integer
                    description: The x402 protocol version the response follows.
                    example: 2
                  items:
                    type: array
                    description: Array of service listings.
                    items:
                      $ref: '#/components/schemas/ServiceListing'
                  pagination:
                    $ref: '#/components/schemas/Pagination'
              example:
                x402Version: 2
                items:
                  - resource: https://api.aisa.one/apis/v2/coingecko/simple/price
                    type: http
                    x402Version: 2
                    lastUpdated: '2026-06-25T16:40:14.015Z'
                    accepts:
                      - scheme: exact
                        network: eip155:8453
                        asset: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
                        amount: '10000'
                        payTo: '0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed'
                        extra:
                          name: USD Coin
                          version: '2'
                    metadata:
                      provider:
                        name: AIsa API
                        description: cryptocurrency market data prices
                        category: FINANCIAL_ANALYSIS
                        tags:
                          - x402
                          - crypto
                          - market-data
                        website: https://aisa.one
                        docsUrl: https://aisa.one/docs/api-reference
                        openApiUrl: https://aisa.one/openapi.yaml
                      path: /apis/v2/coingecko/simple/price
                      method: GET
                      description: Get cryptocurrency prices in multiple currencies
                      mimeType: application/json
                      input:
                        type: object
                        properties:
                          ids:
                            type: string
                      output:
                        type: object
                      siwx: false
                      supportsVanillax402: true
                      supportsCircleGateway: true
                pagination:
                  limit: 50
                  offset: 0
                  total: 636
      security: []
components:
  schemas:
    ServiceListing:
      type: object
      description: A single x402-compatible service in the marketplace catalog.
      properties:
        resource:
          type: string
          description: The URL of the service endpoint.
          example: https://api.aisa.one/apis/v2/coingecko/simple/price
        type:
          type: string
          description: Protocol type (`http` or `mcp`).
          enum:
            - http
            - mcp
          example: http
        x402Version:
          type: integer
          description: x402 protocol version for this listing.
          example: 2
        lastUpdated:
          type: string
          format: date-time
          description: ISO-8601 timestamp of the last catalog update.
          example: '2026-06-25T16:40:14.015Z'
        accepts:
          type: array
          description: >-
            Payment requirements the service accepts. Each entry carries the
            `network` (CAIP-2), the `asset` (token contract address), the
            `scheme`, the `amount`, and the `payTo` seller wallet. `amount` is
            in atomic units — USDC has 6 decimals, so `10000` equals 0.01 USDC.
            v2 uses `amount` (v1 used `maxAmountRequired`).
          items:
            $ref: '#/components/schemas/PaymentAcceptance'
        metadata:
          $ref: '#/components/schemas/ServiceMetadata'
    Pagination:
      type: object
      description: Pagination metadata for the response.
      properties:
        limit:
          type: integer
          description: Number of items returned.
          example: 50
        offset:
          type: integer
          description: Number of items skipped.
          example: 0
        total:
          type: integer
          description: Total number of matching items in the catalog.
          example: 636
    PaymentAcceptance:
      type: object
      description: A single payment option accepted by the service.
      properties:
        scheme:
          type: string
          description: Payment scheme (for example, `exact`).
          example: exact
        network:
          type: string
          description: CAIP-2 blockchain identifier.
          example: eip155:8453
        asset:
          type: string
          description: Token contract address.
          example: '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
        amount:
          type: string
          description: >-
            Payment amount in atomic units. USDC has 6 decimals, so `10000`
            equals 0.01 USDC.
          example: '10000'
        payTo:
          type: string
          description: Seller wallet address.
          example: '0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed'
        extra:
          type: object
          description: Additional token metadata.
          properties:
            name:
              type: string
              example: USD Coin
            version:
              type: string
              example: '2'
    ServiceMetadata:
      type: object
      description: >-
        Service metadata including provider details, request shape, and
        capability flags.
      properties:
        provider:
          type: object
          description: Information about the service provider.
          properties:
            name:
              type: string
              example: AIsa API
            description:
              type: string
              example: cryptocurrency market data prices
            category:
              type: string
              description: Service category.
              enum:
                - SOCIAL_INTELLIGENCE
                - FINANCIAL_ANALYSIS
                - WEB_SEARCH_RESEARCH
                - PREDICTION_MARKETS
                - CREATIVE
                - INFRASTRUCTURE
              example: FINANCIAL_ANALYSIS
            tags:
              type: array
              items:
                type: string
              example:
                - x402
                - crypto
                - market-data
            website:
              type: string
              example: https://aisa.one
            docsUrl:
              type: string
              example: https://aisa.one/docs/api-reference
            openApiUrl:
              type: string
              example: https://aisa.one/openapi.yaml
        path:
          type: string
          description: The request path for the service.
          example: /apis/v2/coingecko/simple/price
        method:
          type: string
          description: The HTTP method for the service.
          example: GET
        description:
          type: string
          example: Get cryptocurrency prices in multiple currencies
        mimeType:
          type: string
          example: application/json
        input:
          type: object
          description: JSON Schema describing the service's request input.
        output:
          type: object
          description: JSON Schema describing the service's response output.
        siwx:
          type: boolean
          description: >-
            Whether the service requires browser-based Sign-In With X (SIWX)
            authentication.
          example: false
        supportsVanillax402:
          type: boolean
          description: Whether the service accepts onchain x402 payments.
          example: true
        supportsCircleGateway:
          type: boolean
          description: >-
            Whether the service accepts Circle Gateway offchain batched
            payments.
          example: true

````