Sleeper Leagues API

openapi: 3.1.0
info:
  title: Sleeper Drafts Leagues API
  version: '1.0'
  description: The Sleeper API is a read-only HTTP API that exposes public fantasy sports data — users, leagues, rosters, matchups, transactions, drafts, draft picks, traded picks, and players. It is free to use and requires no API token, because no content can be modified through it. All endpoints are GET requests that return JSON.
  contact:
    name: Sleeper API Docs
    url: https://docs.sleeper.com/
  x-provenance:
    generated: '2026-07-21'
    method: generated
    source: https://docs.sleeper.com/
    note: Authored by the API Evangelist enrichment pipeline from the operations documented at docs.sleeper.com. Sleeper does not publish an OpenAPI; every path, method, and parameter here is transcribed from the public docs.
servers:
- url: https://api.sleeper.app/v1
  description: Sleeper read-only API (v1)
tags:
- name: Leagues
paths:
  /user/{user_id}/leagues/{sport}/{season}:
    get:
      operationId: getUserLeagues
      summary: Get all leagues for a user
      description: All leagues a user is a member of for a given sport and season.
      tags:
      - Leagues
      parameters:
      - name: user_id
        in: path
        required: true
        schema:
          type: string
      - name: sport
        in: path
        required: true
        schema:
          type: string
          example: nfl
      - name: season
        in: path
        required: true
        schema:
          type: string
          example: '2025'
      responses:
        '200':
          description: Array of league objects.
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/League'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/TooManyRequests'
  /league/{league_id}:
    get:
      operationId: getLeague
      summary: Get a specific league
      tags:
      - Leagues
      parameters:
      - name: league_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: A league object.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/League'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/TooManyRequests'
  /league/{league_id}/rosters:
    get:
      operationId: getLeagueRosters
      summary: Get all rosters in a league
      tags:
      - Leagues
      parameters:
      - name: league_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Array of roster objects.
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/Roster'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/TooManyRequests'
  /league/{league_id}/users:
    get:
      operationId: getLeagueUsers
      summary: Get all users in a league
      tags:
      - Leagues
      parameters:
      - name: league_id
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Array of user objects (with league-specific metadata).
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/User'
        '404':
          $ref: '#/components/responses/NotFound'
        '429':
          $ref: '#/components/responses/TooManyRequests'
components:
  schemas:
    Roster:
      type: object
      properties:
        roster_id:
          type: integer
        owner_id:
          type: string
          description: References a User by user_id
        league_id:
          type: string
          description: References a League by league_id
        players:
          type: array
          items:
            type: string
          description: player_id references
        starters:
          type: array
          items:
            type: string
          description: player_id references
        reserve:
          type: array
          items:
            type: string
        settings:
          type: object
    League:
      type: object
      properties:
        league_id:
          type: string
        name:
          type: string
        status:
          type: string
          description: e.g. pre_draft
          drafting: null
          in_season: null
          complete: null
        sport:
          type: string
        season:
          type: string
        season_type:
          type: string
        total_rosters:
          type: integer
        settings:
          type: object
        scoring_settings:
          type: object
        roster_positions:
          type: array
          items:
            type: string
        previous_league_id:
          type: string
          description: References the prior season League by league_id
        draft_id:
          type: string
          description: References the Draft by draft_id
        avatar:
          type: string
    User:
      type: object
      properties:
        user_id:
          type: string
        username:
          type: string
        display_name:
          type: string
        avatar:
          type: string
          description: Avatar id; resolve at https://sleepercdn.com/avatars/{avatar}
        metadata:
          type: object
  responses:
    NotFound:
      description: The requested resource was not found.
    TooManyRequests:
      description: Rate limit exceeded — stay under 1000 API calls per minute to avoid IP blocks.