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

# Create NGN rails swap

> Swaps CNGN ↔ USDC/USDT on the customer's StRails Smart Wallet via `POST /swap`.
Customer must be linked to a StRails user. Requires `transfers:write` and `Idempotency-Key`.




## OpenAPI

````yaml /openapi.yaml post /rails/swaps
openapi: 3.1.0
info:
  title: Remitflex API
  version: 1.0.0
  description: >
    Programmatic access to Remitflex payment routes, fiat rates, customers, and
    transactions.


    **Dashboard:** Create API keys at https://dashboard.remitflex.io


    **Authentication:** Send your API key as `Authorization: Bearer
    rmf_live_...` or `rmf_test_...`.


    **Idempotency:** Mutating requests (`POST`, `PUT`, `PATCH`, `DELETE`)
    require an `Idempotency-Key` header when authenticated with an API key.
servers:
  - url: http://localhost:4000/v1
    description: Local development
  - url: https://api.remitflex.io/v1
    description: Production
security:
  - ApiKeyAuth: []
paths:
  /rails/swaps:
    post:
      tags:
        - NGN rails
      summary: Create NGN rails swap
      description: >
        Swaps CNGN ↔ USDC/USDT on the customer's StRails Smart Wallet via `POST
        /swap`.

        Customer must be linked to a StRails user. Requires `transfers:write`
        and `Idempotency-Key`.
      operationId: createRailsSwap
      parameters:
        - $ref: '#/components/parameters/IdempotencyKey'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - sellToken
                - buyToken
                - amount
              properties:
                customerId:
                  type: string
                  format: uuid
                sellToken:
                  type: string
                  enum:
                    - CNGN
                    - USDC
                    - USDT
                buyToken:
                  type: string
                  enum:
                    - CNGN
                    - USDC
                    - USDT
                amount:
                  type: number
                slippage:
                  type: number
                smartWalletAddress:
                  type: string
                destinationAddress:
                  type: string
            example:
              sellToken: CNGN
              buyToken: USDC
              amount: 5000
      responses:
        '201':
          description: Rails swap created
        '422':
          description: Customer not linked to StRails
      security:
        - ApiKeyAuth: []
components:
  parameters:
    IdempotencyKey:
      name: Idempotency-Key
      in: header
      required: true
      description: >-
        Unique key for safe retries on mutating API-key requests. Cached for 24
        hours per org, method, and path.
      schema:
        type: string
        maxLength: 255
        example: 7f3c2a1b-4e5d-6c7b-8a9f-0e1d2c3b4a5f
  securitySchemes:
    ApiKeyAuth:
      type: http
      scheme: bearer
      description: >
        API key created in the Remitflex Dashboard at dashboard.remitflex.io
        (`rmf_live_...` or `rmf_test_...`).

        Key management endpoints require a dashboard JWT and are not part of
        this reference.

````