# List Event Contract Categories

Retrieves all categories under the Event Contract.

# OpenAPI definition

```json
{
  "info": {
    "title": "Webull OpenAPI Documentation",
    "description": "The Webull OpenAPI enables integration of trading APIs, market data, and OAuth authentication for building trading applications and brokerage solutions. It supports HTTP-based historical and real-time market data and MQTT streaming via WebSocket/TCP, along with SDKs, secure authentication, and APIs for orders, accounts, and event contract trading.",
    "contact": {
      "name": "Webull Developer Support",
      "url": "https://www.webull.com/help",
      "email": "api-support@webull-us.com"
    },
    "version": "2.0",
    "x-logo": {
      "url": "static/png/logo.png"
    }
  },
  "servers": [
    {
      "url": "https://api.sandbox.webull.com"
    }
  ],
  "path": "/trading/instruments/event-contracts/categories/list",
  "method": "get",
  "tags": [
    "Instruments"
  ],
  "description": "Retrieves all categories under the Event Contract.",
  "operationId": "eventCategoriesList",
  "parameters": [
    {
      "name": "x-app-key",
      "in": "header",
      "description": "A unique identifier issued to a developer for accessing an application's API.",
      "required": true,
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        "1.0": {
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    {
      "name": "x-signature-algorithm",
      "in": "header",
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      "required": true,
      "schema": {
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        "default": "HMAC-SHA1"
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      "in": "header",
      "description": "Signature unique random number.",
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      "schema": {
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      "required": true,
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      "required": true,
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  ],
  "responses": {
    "200": {
      "description": "OK",
      "content": {
        "application/json": {
          "schema": {
            "type": "array",
            "items": {
              "required": [
                "category_code",
                "category_id",
                "category_name"
              ],
              "type": "object",
              "properties": {
                "category_id": {
                  "type": "integer",
                  "description": "Category ID.",
                  "format": "int32",
                  "example": 1
                },
                "category_code": {
                  "type": "string",
                  "description": "Unique identifier code for category.",
                  "example": "ECONOMICS"
                },
                "category_name": {
                  "type": "string",
                  "description": "Category corresponding name.",
                  "example": "Economics"
                }
              },
              "description": "Event Categories",
              "title": "EventCategoriesVo"
            }
          }
        }
      }
    },
    "401": {
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      "content": {
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  },
  "postman": {
    "name": "List Event Contract Categories",
    "description": {
      "content": "Retrieves all categories under the Event Contract.",
      "type": "text/plain"
    },
    "url": {
      "path": [
        "trading",
        "instruments",
        "event-contracts",
        "categories",
        "list"
      ],
      "host": [
        "{{baseUrl}}"
      ],
      "query": [],
      "variable": []
    },
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        "description": {
          "content": "(Required) A unique identifier issued to a developer for accessing an application's API.",
          "type": "text/plain"
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        "value": ""
      },
      {
        "disabled": false,
        "description": {
          "content": "(Required) A unique key issued to developers to access the application's API.",
          "type": "text/plain"
        },
        "key": "x-app-secret",
        "value": ""
      },
      {
        "disabled": false,
        "description": {
          "content": "(Required) Timestamp of the request, follows ISO8601 format: YYYY-MM-DDThh:mm:ssZ, e.g. 2023-07-16T19:23:51Z, only supports UTC time zone.",
          "type": "text/plain"
        },
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        "value": ""
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        "description": {
          "content": "(Required) Signature algorithm version, default is 1.0.",
          "type": "text/plain"
        },
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        "description": {
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          "type": "text/plain"
        },
        "key": "x-signature-algorithm",
        "value": ""
      },
      {
        "disabled": false,
        "description": {
          "content": "(Required) Signature unique random number.",
          "type": "text/plain"
        },
        "key": "x-signature-nonce",
        "value": ""
      },
      {
        "disabled": false,
        "description": {
          "content": "(Required) An access token is a credential that represents the authorization granted to a client (e.g., a user or an application) to access specific protected resources on behalf of a user, without needing to share their password.",
          "type": "text/plain"
        },
        "key": "x-access-token",
        "value": ""
      },
      {
        "disabled": false,
        "description": {
          "content": "(Required) API interface version. Supported values: `v2`, `v3`.",
          "type": "text/plain"
        },
        "key": "x-version",
        "value": ""
      },
      {
        "disabled": false,
        "description": {
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          "type": "text/plain"
        },
        "key": "x-signature",
        "value": ""
      },
      {
        "key": "Accept",
        "value": "application/json"
      }
    ],
    "method": "GET"
  }
}
```