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

# List available coins

> Returns the union of base coins (BTC, ETH, SOL, XRP, etc.) across all exchanges.



## OpenAPI

````yaml /openapi.yaml get /coins
openapi: 3.1.0
info:
  title: GammaFlip GEX API
  version: 1.0.0
  description: |
    Programmatic access to Gamma Exposure (GEX) data for cryptocurrency options.

    Requires a **Pro subscription** (€35/month) or an active trial. Trial users
    are limited to 50 requests/day; Pro users get 500 requests/day.
  contact:
    name: GammaFlip Support
    email: admin@gammaflip.io
    url: https://gammaflip.io
servers:
  - url: https://api.gammaflip.io/api/v1
    description: Production
security:
  - ApiKeyAuth: []
paths:
  /coins:
    get:
      tags:
        - Discovery
      summary: List available coins
      description: >-
        Returns the union of base coins (BTC, ETH, SOL, XRP, etc.) across all
        exchanges.
      operationId: listCoins
      responses:
        '200':
          description: Coin list
          content:
            application/json:
              schema:
                allOf:
                  - $ref: '#/components/schemas/Envelope'
                  - type: object
                    properties:
                      data:
                        type: object
                        properties:
                          coins:
                            type: array
                            items:
                              type: string
                            example:
                              - BTC
                              - ETH
                              - SOL
                              - XRP
        '401':
          $ref: '#/components/responses/Unauthorized'
        '403':
          $ref: '#/components/responses/Forbidden'
        '429':
          $ref: '#/components/responses/RateLimited'
components:
  schemas:
    Envelope:
      type: object
      required:
        - data
        - meta
      properties:
        data:
          type: object
          description: The response payload.
        meta:
          type: object
          properties:
            timestamp:
              type: string
              format: date-time
              example: '2026-04-14T10:00:00+00:00'
            exchange:
              type: string
              example: all
            coin:
              type: string
              example: BTC
            rate_limit:
              $ref: '#/components/schemas/RateLimit'
    RateLimit:
      type: object
      properties:
        limit:
          type: integer
          example: 500
        remaining:
          type: integer
          example: 487
        reset:
          type: string
          format: date-time
          example: '2026-04-15T00:00:00+00:00'
    Error:
      type: object
      required:
        - error
        - message
      properties:
        error:
          type: string
          enum:
            - unauthorized
            - subscription_required
            - rate_limit_exceeded
            - invalid_exchange
            - no_data
          example: rate_limit_exceeded
        message:
          type: string
          example: Daily limit of 500 reached.
        current_tier:
          type: string
          example: free
  responses:
    Unauthorized:
      description: Invalid or missing API key
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    Forbidden:
      description: Subscription required
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    RateLimited:
      description: Daily rate limit exceeded
      headers:
        X-RateLimit-Limit:
          schema:
            type: integer
        X-RateLimit-Remaining:
          schema:
            type: integer
            example: 0
        X-RateLimit-Reset:
          schema:
            type: string
            format: date-time
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
      description: |
        API key prefixed with `gex_sk_`. Create one in your
        [account dashboard](https://gammaflip.io/account).

````