ADEXTO X402 API

openapi: 3.2.0
info:
  title: ADEXTO gateway X402 API
  version: 1.1.0
  description: Buy any ADEXTO bonding-curve market with USDC on Base and receive the token on the market's own chain (0G, Base, Arbitrum One, Monad, Robinhood Chain, Arc). No bridge, no gas on the destination chain. Delivery is executed before the charge, so a failed fill costs the gateway, not the buyer.
  x-guidance: 'GET /v1/x402/buy/{symbol} without payment returns 402 with a live quote in "quote" and the payment terms in accepts[0] (exact scheme, USDC on Base, EIP-3009). Sign transferWithAuthorization for exactly maxAmountRequired to payTo, base64-encode {x402Version, scheme, network, payload:{signature, authorization}}, and repeat the request with it in the X-PAYMENT header. x402 v2 clients such as @x402/fetch can use the PAYMENT-REQUIRED header instead: the same terms with network eip155:8453, paid back in PAYMENT-SIGNATURE. Pass ?chain=<id> when a ticker trades on more than one chain and ?to=<address> to deliver to another wallet. Market list: https://adexto.xyz/api/graphql. The same flow is available as MCP tools at https://adexto.xyz/api/mcp.'
  contact:
    name: ADEXTO
    url: https://adexto.xyz/contact
servers:
- url: https://x402.adexto.xyz
tags:
- name: X402
paths:
  /v1/x402/buy/{symbol}:
    get:
      operationId: buyMarket
      summary: Buy a market's token with 0.10 USDC on Base, delivered on the market's own chain
      description: 'Unpaid: 402 with the quote and accepts[0]. Paid (X-PAYMENT, or PAYMENT-SIGNATURE for x402 v2): the curve buys the token for the payer on the market''s chain, then the USDC authorization is settled. Refusals that happen before any charge: unknown market (404), market not tradable (409), out of inventory (503).'
      security: []
      parameters:
      - name: symbol
        in: path
        required: true
        description: Market ticker, case-insensitive.
        schema:
          type: string
          pattern: ^[A-Za-z0-9]{2,12}$
        examples:
          bm-16661:
            value: bm
          sai-5042:
            value: sai
          loop-42161:
            value: loop
          loop-143:
            value: loop
          sai-143:
            value: sai
          sai-42161:
            value: sai
          sai-4663:
            value: sai
          zeebo-16661:
            value: zeebo
          wombo-42161:
            value: wombo
          bloop-8453:
            value: bloop
          parcel-143:
            value: parcel
          adt-16661:
            value: adt
      - name: chain
        in: query
        required: false
        description: Chain id of the market, for a ticker that trades on more than one chain.
        schema:
          type: integer
      - name: to
        in: query
        required: false
        description: Address that receives the tokens. Defaults to the address that signed the payment.
        schema:
          type: string
          pattern: ^0x[a-fA-F0-9]{40}$
      - name: X-PAYMENT
        in: header
        required: false
        description: Base64 x402 payment payload. Omit it to receive the 402 quote.
        schema:
          type: string
      - name: PAYMENT-SIGNATURE
        in: header
        required: false
        description: The same payment in the x402 v2 envelope, as sent by @x402/fetch. Use one header, not both.
        schema:
          type: string
      x-payment-info:
        price:
          mode: fixed
          currency: USD
          amount: '0.10'
        protocols:
        - x402:
            scheme: exact
            network: base
            asset: USDC
      responses:
        '200':
          description: Delivered and settled. delivery.transaction is the buy on the market's chain.
          content:
            application/json:
              schema:
                type: object
              example:
                symbol: PARCEL
                delivery:
                  success: true
                  transaction: 0x…
                  chainId: 143
                  to: 0x… (the payer unless ?to= is given)
                  minTokensOut: …
                settlement:
                  success: true
                  transaction: 0x…
                  network: base
                  amount: '100000'
        '402':
          description: 'Payment Required: quote plus accepts[0], or a payment that failed verification.'
        '404':
          description: Unknown market. No payment was taken.
        '409':
          description: Market not tradable. No payment was taken.
        '503':
          description: Quote, inventory or chain unavailable. No payment was taken.
      tags:
      - X402
externalDocs:
  description: x402 integration reference
  url: https://adexto.xyz/x402