openapi: 3.1.0
info:
  title: Open Trivia DB Categories API
  description: Free JSON API providing trivia questions across multiple categories, difficulties, and types. No API key is required. Supports session tokens to avoid duplicate questions across requests, multiple response encodings, and rate limiting of one request per IP every 5 seconds.
  version: '1.0'
  contact:
    name: Open Trivia DB
    url: https://opentdb.com
  license:
    name: Creative Commons Attribution-ShareAlike 4.0 International
    url: https://creativecommons.org/licenses/by-sa/4.0/
servers:
- url: https://opentdb.com
  description: Open Trivia DB Production
tags:
- name: Categories
  description: Retrieve available trivia categories.
paths:
  /api_category.php:
    get:
      tags:
      - Categories
      summary: List trivia categories
      description: Returns all available trivia categories with IDs and names.
      operationId: getCategories
      responses:
        '200':
          description: List of categories.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CategoriesResponse'
  /api_count.php:
    get:
      tags:
      - Categories
      summary: Question count for category
      description: Returns the total and remaining question counts for a category.
      operationId: getCategoryCount
      parameters:
      - name: category
        in: query
        required: true
        description: Category ID.
        schema:
          type: integer
      responses:
        '200':
          description: Category question count.
  /api_count_global.php:
    get:
      tags:
      - Categories
      summary: Global question counts
      description: Returns global question counts across all categories.
      operationId: getGlobalCount
      responses:
        '200':
          description: Global counts response.
components:
  schemas:
    CategoriesResponse:
      type: object
      properties:
        trivia_categories:
          type: array
          items:
            type: object
            properties:
              id:
                type: integer
              name:
                type: string
externalDocs:
  description: Open Trivia DB API Documentation
  url: https://opentdb.com/api_config.php