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

# List Categories

> Top-level navigation tree for sports discovery - all supported sports and leagues

## Overview

Returns the top-level navigation tree for sports discovery. The response is a hierarchy of **category → sport → league**.

At launch, the only supported category is `sports`. Within sports, each distinct sport (basketball, soccer, hockey, baseball) is listed, and under each sport the leagues currently available in the canonical sports dataset.

This endpoint is the intended entry point for client UIs - use it to build filter dropdowns or sport/league pickers, then pass the `league` or `sport` value to `GET /v2/sports/markets` to retrieve actual games.

<Info>
  Only leagues with at least one currently available canonical sports game are returned. Leagues with no available games will not appear until a new game is listed by a venue and matched into the canonical sports tables.
</Info>

## Response Fields

| Field                                         | Description                                                                                                      |
| --------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| `categories[].category`                       | Top-level category identifier. Always `"sports"` at launch.                                                      |
| `categories[].sports[].sport`                 | Sport identifier - pass to `/v2/sports/markets?sport=...`. Values: `basketball`, `soccer`, `hockey`, `baseball`. |
| `categories[].sports[].leagues[].league`      | League code - pass to `/v2/sports/markets?league=...` (e.g. `nba`, `epl`).                                       |
| `categories[].sports[].leagues[].league_name` | Human-readable league name (e.g. `"NBA"`, `"Premier League"`).                                                   |

## Example Response

```json theme={null}
{
  "categories": [
    {
      "category": "sports",
      "sports": [
        {
          "sport": "basketball",
          "leagues": [
            { "league": "nba", "league_name": "NBA" }
          ]
        },
        {
          "sport": "soccer",
          "leagues": [
            { "league": "epl", "league_name": "Premier League" },
            { "league": "sea", "league_name": "Serie A" },
            { "league": "lal", "league_name": "La Liga" },
            { "league": "ucl", "league_name": "Champions League" }
          ]
        }
      ]
    }
  ]
}
```

## Notes

* `sport` values are lowercase English. Passing a league code (e.g. `sport=nba`) returns no results - use `league=nba` instead.
* `league` values are 2–4 character lowercase codes. See the [Sports Markets concept page](/concepts/sports-markets) for the current coverage matrix per venue.
* The response is a complete snapshot - there is no pagination.
* Cached for 60 seconds.


## OpenAPI

````yaml GET /v2/sports/categories
openapi: 3.1.0
info:
  title: Predexon Enterprise API
  description: Unified cross-venue prediction market discovery
  version: 1.0.0
servers:
  - url: https://api.predexon.com
security:
  - apiKey: []
paths:
  /v2/sports/categories:
    get:
      tags:
        - sports
      summary: List Categories
      description: |-
        List available sports categories.

        Returns hierarchy of sport -> leagues with game counts.
        Only includes categories with active matched games.
      operationId: list_categories_v2_sports_categories_get
      responses:
        '200':
          description: Successful response
          content:
            application/json:
              schema: {}
              example:
                categories:
                  - category: sports
                    sports:
                      - sport: basketball
                        leagues:
                          - league: nba
                            league_name: NBA
                      - sport: soccer
                        leagues:
                          - league: epl
                            league_name: Premier League
                          - league: lal
                            league_name: La Liga
                          - league: sea
                            league_name: Serie A
                          - league: ucl
                            league_name: Champions League
components:
  securitySchemes:
    apiKey:
      type: apiKey
      in: header
      name: x-api-key
      description: >-
        Data key provided by Predexon. The trading key used by the Order Router
        on trade.predexon.com is a separate credential.

````