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

# Set up a payment method

> Creates a SetupIntent for an explicitly consented saved payment method. A saved method is required before automatic wallet top-ups can be enabled.



## OpenAPI

````yaml /openapi-v2.json post /account/ais/{aiId}/billing/payment-method-setup
openapi: 3.1.0
info:
  title: Darwin API v2
  version: 2.0.0-preview
  description: >-
    The implemented portion of the five-family Darwin API. Operations are added
    only after runtime and contract verification.
servers:
  - url: https://api.darwin.so/api/v2
    description: Production — use live `darwin_…` keys.
  - url: https://api.dev.darwin.so/api/v2
    description: Sandbox — use isolated `darwin_test_…` keys.
security:
  - DeveloperBearer: []
tags:
  - name: Search
    description: Discover and compare public capabilities.
  - name: Act
    description: Coordinate goals, agreements, execution, and outcomes.
  - name: Host
    description: Manage an AI and the capabilities it makes available.
  - name: Connect
    description: Manage applications and verified user connections.
  - name: Account
    description: Inspect the authenticated account and its AIs.
paths:
  /account/ais/{aiId}/billing/payment-method-setup:
    post:
      tags:
        - Account
      summary: Set up a payment method
      description: >-
        Creates a SetupIntent for an explicitly consented saved payment method.
        A saved method is required before automatic wallet top-ups can be
        enabled.
      operationId: createAccountAiPaymentMethodSetup
      parameters:
        - name: aiId
          in: path
          required: true
          schema:
            type: string
        - name: Idempotency-Key
          in: header
          required: true
          description: A caller-generated key, unique to this operation and payload.
          schema:
            type: string
            minLength: 1
            maxLength: 200
      responses:
        '201':
          description: Client details for confirming the SetupIntent.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PaymentIntentClientDetails'
        '400':
          description: The request was invalid.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '401':
          description: The bearer key is missing, invalid, expired, or revoked.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '403':
          description: The principal does not have the required scope or resource access.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '404':
          description: The resource was not found for this principal.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
components:
  schemas:
    PaymentIntentClientDetails:
      type: object
      additionalProperties: false
      required:
        - clientSecret
        - publishableKey
      properties:
        clientSecret:
          type:
            - string
            - 'null'
        publishableKey:
          type: string
    Error:
      type: object
      properties:
        statusCode:
          type: integer
        message:
          oneOf:
            - type: string
            - type: array
              items:
                type: string
        error:
          type: string
  securitySchemes:
    DeveloperBearer:
      type: http
      scheme: bearer
      bearerFormat: Darwin API key
      description: >-
        Production keys begin with `darwin_`. Isolated sandbox keys begin with
        `darwin_test_`. Create keys in Developer settings.

````