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

# Connect an exchange

> Start an exchange connection and return the authorization URL.

Starts a connection and returns the URL the user authorizes at. Once they
finish, [Get exchange connection status](/api/exchange/status) reports
`connected: true`.


## OpenAPI

````yaml api/openapi.json POST /v1/exchange/{exchange}
openapi: 3.1.0
info:
  description: Fiat-to-USDC onramp API. The URL prefix (`/v1`) is the version contract.
  license:
    identifier: LicenseRef-Proprietary
    name: Proprietary
  title: Calm API
  version: v1
servers:
  - description: Production
    url: https://api.calmtreasury.xyz
  - description: Sandbox
    url: https://api.sandbox.calmtreasury.xyz
security: []
paths:
  /v1/exchange/{exchange}:
    post:
      summary: Connect an exchange
      description: >-
        Starts an exchange connection for the `wallet` in the body and returns
        the URL the user authorizes at. On success, the connection turns live
        and can be read via `GET /v1/exchange/{exchange}`.
      operationId: connectExchange
      parameters:
        - in: path
          name: exchange
          required: true
          schema:
            enum:
              - coinbase
            type: string
      requestBody:
        content:
          application/json:
            schema:
              properties:
                wallet:
                  pattern: ^0x[a-fA-F0-9]{40}$
                  type: string
              required:
                - wallet
              type: object
        required: true
      responses:
        '200':
          content:
            application/json:
              schema:
                properties:
                  is_qr_code:
                    type: boolean
                  url:
                    format: uri
                    type: string
                required:
                  - url
                  - is_qr_code
                type: object
          description: The authorization URL.
        '400':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
          description: >-
            Bad Request — `error.code` includes: generic_invalid_request,
            generic_validation_error, publishable_key_missing,
            unsupported_exchange, validation_error.
        '401':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
          description: 'Unauthorized — `error.code` includes: invalid_publishable_key.'
        '403':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
          description: 'Forbidden — `error.code` includes: origin_not_allowed.'
        '429':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
          description: 'Too Many Requests — `error.code` includes: rate_limited.'
        '502':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
          description: >-
            Bad Gateway — `error.code` includes:
            apikey_insufficient_permissions, exchange_provider_error,
            generic_internal_server_error, generic_unauthorized,
            oauth_authorization_failed, oauth_insufficient_scope,
            oauth_invalid_state, oauth_token_exchange_failed.
      security:
        - publishableKey: []
components:
  schemas:
    Error:
      properties:
        error:
          properties:
            code:
              type: string
            message:
              type: string
          required:
            - code
            - message
          type: object
      required:
        - error
      type: object
  securitySchemes:
    publishableKey:
      description: Publishable key identifying the calling app.
      in: header
      name: x-calm-publishable-key
      type: apiKey

````