Sleeper

Sleeper is a fantasy sports platform — a mobile-first app for creating and managing fantasy football, basketball, and other sports leagues with chat, drafts, waivers, and real-time scoring built in. Sleeper publishes a free, read-only HTTP API at api.sleeper.app that exposes public fantasy data: users, leagues, rosters, matchups, transactions, drafts, draft picks, traded picks, trending players, and the current sport/season state. The API requires no API token or OAuth because no content can be modified through it; every endpoint is a GET request returning JSON, and callers are asked to stay under 1,000 requests per minute to avoid IP blocks. Sleeper is backed by a16z and General Catalyst.

Sleeper publishes 8 API contracts indexed on the APIs.io network, including Drafts API, Leagues API, Matchups API, and 5 more. Tagged areas include Company, Fantasy Sports, Sports, Fantasy Football, and Gaming.

The Sleeper catalog on APIs.io includes 1 Spectral governance ruleset.

Sleeper’s developer surface includes documentation, API reference, signup flow, support, engineering blog, authentication, and 16 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

30.2/100 thin ▬ flat Agent 21/100 agent aware Front door AI 1/6 silent Heartbeat 0/100 dormant saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

1 published contract 3 Agent Skills

Company Fantasy Sports SportsFantasy FootballGaming Sports Data League Consumer

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 30.2/100 · thin

Contract Quality 2.6 / 21

Developer Ergonomics 8.0 / 17

Access Clarity 5.8 / 17

Operational Transparency 0.0 / 11

Contract Governance 1.9 / 10

Discoverability 6.2 / 9

Regulatory Posture 3.7 / 15

Agent readiness — 21/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 4 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics does not apply to this provider. The published contracts declare no write operations, and a read-only API cannot create-or-update. The facet is excluded from this provider's denominator entirely — not scored zero. A reference or data API is not deficient for being unable to upsert.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document

7 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 12.3 — up to +21.9 composite points
Access Clarity scores 34.2 — up to +13.2 composite points
Operational Transparency scores 0.0 — up to +13.0 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/sleeper/apis.yml: open an issue on github.com/api-evangelist/sleeper to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 1

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

APIs 8

Individual APIs this provider publishes, each with its own machine-readable definition.

Sleeper Drafts API

The Drafts API from Sleeper — 6 operation(s) for drafts.

Sleeper Leagues API

The Leagues API from Sleeper — 4 operation(s) for leagues.

Sleeper Matchups API

The Matchups API from Sleeper — 1 operation(s) for matchups.

Sleeper Players API

The Players API from Sleeper — 2 operation(s) for players.

Sleeper Playoffs API

The Playoffs API from Sleeper — 2 operation(s) for playoffs.

Sleeper State API

The State API from Sleeper — 1 operation(s) for state.

Sleeper Transactions API

The Transactions API from Sleeper — 1 operation(s) for transactions.

Sleeper Users API

The Users API from Sleeper — 1 operation(s) for users.

Scroll for all 8

Open Collections 8

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Sleeper Drafts API

OPEN COLLECTION

Sleeper Drafts Leagues API

OPEN COLLECTION

Sleeper Drafts Matchups API

OPEN COLLECTION

Sleeper Drafts Players API

OPEN COLLECTION

Sleeper Drafts Playoffs API

OPEN COLLECTION

Sleeper Drafts State API

OPEN COLLECTION

Sleeper Drafts Transactions API

OPEN COLLECTION

Sleeper Drafts Users API

OPEN COLLECTION

Scroll for all 8

Agent Skills 3

Packaged agent skills for driving this provider's APIs from an AI assistant.

Read a draft's picks and trends

AGENT SKILL

Get a league's teams and weekly matchups

AGENT SKILL

Find a user's leagues and drafts

AGENT SKILL

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Sleeper API Rules

51 rules · 49 errors 1 warnings 1 info

SPECTRAL

OpenAPI Overlays 1

Overlays applied on top of this provider's contracts. Each card says who wrote it: a document the provider publishes, or one API Evangelist derived or generated.

Sleeper Openapi Overlay

3 actions · update · sleeper-openapi.yml

DERIVED

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Sleeper Authentication

none · 0 schemes

SECURITY

Sleeper Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

SignUp

SignUp

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

X-MCPServerCandidate

LLMsTxt

WellKnown

AgentSkill

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

ErrorCatalog

Conventions

DataModel

Conformance

Lifecycle

Build 1

SDKs, sample code, and the tooling you integrate with

Packages

Packages

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: sleeper
name: Sleeper
description: 'Sleeper is a fantasy sports platform — a mobile-first app for creating and managing fantasy football, basketball,
  and other sports leagues with chat, drafts, waivers, and real-time scoring built in. Sleeper publishes a free, read-only
  HTTP API at api.sleeper.app that exposes public fantasy data: users, leagues, rosters, matchups, transactions, drafts, draft
  picks, traded picks, trending players, and the current sport/season state. The API requires no API token or OAuth because
  no content can be modified through it; every endpoint is a GET request returning JSON, and callers are asked to stay under
  1,000 requests per minute to avoid IP blocks. Sleeper is backed by a16z and General Catalyst.'
url: https://raw.githubusercontent.com/api-evangelist/sleeper/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- a16z
- general-catalyst
x-tier: profiled
x-tier-reason: has-public-api
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-11-06'
  method: derived
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-21'
image: https://sleepercdn.com/images/v2/icons/app_icon_web.png
tags:
- Company
- Fantasy Sports
- Sports
- Fantasy Football
- Gaming
- Sports Data
- League
- Consumer
tags_raw:
- Company
- Fantasy Sports
- Sports
- Fantasy Football
- Gaming
- Sports Data
- Leagues
- Consumer
apis:
- aid: sleeper:sleeper-drafts-api
  name: Sleeper Drafts API
  description: The Drafts API from Sleeper — 6 operation(s) for drafts.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - Drafts
  properties:
  - type: OpenAPI
    url: openapi/sleeper-drafts-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-leagues-api
  name: Sleeper Leagues API
  description: The Leagues API from Sleeper — 4 operation(s) for leagues.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - League
  tags_raw:
  - Leagues
  properties:
  - type: OpenAPI
    url: openapi/sleeper-leagues-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-matchups-api
  name: Sleeper Matchups API
  description: The Matchups API from Sleeper — 1 operation(s) for matchups.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - Matchups
  properties:
  - type: OpenAPI
    url: openapi/sleeper-matchups-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-players-api
  name: Sleeper Players API
  description: The Players API from Sleeper — 2 operation(s) for players.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - Player
  tags_raw:
  - Players
  properties:
  - type: OpenAPI
    url: openapi/sleeper-players-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-playoffs-api
  name: Sleeper Playoffs API
  description: The Playoffs API from Sleeper — 2 operation(s) for playoffs.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - Playoffs
  properties:
  - type: OpenAPI
    url: openapi/sleeper-playoffs-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-state-api
  name: Sleeper State API
  description: The State API from Sleeper — 1 operation(s) for state.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - States
  tags_raw:
  - State
  properties:
  - type: OpenAPI
    url: openapi/sleeper-state-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-transactions-api
  name: Sleeper Transactions API
  description: The Transactions API from Sleeper — 1 operation(s) for transactions.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - Transaction
  tags_raw:
  - Transactions
  properties:
  - type: OpenAPI
    url: openapi/sleeper-transactions-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
- aid: sleeper:sleeper-users-api
  name: Sleeper Users API
  description: The Users API from Sleeper — 1 operation(s) for users.
  humanURL: https://docs.sleeper.com/
  baseURL: https://api.sleeper.app/v1
  tags:
  - User
  tags_raw:
  - Users
  properties:
  - type: OpenAPI
    url: openapi/sleeper-users-api-openapi.yml
  - type: Documentation
    url: https://docs.sleeper.com/
  - type: APIReference
    url: https://docs.sleeper.com/
common:
- type: Website
  url: https://www.sleeper.com/
- type: DomainSecurity
  url: security/sleeper-domain-security.yml
- type: DeveloperPortal
  url: https://docs.sleeper.com/
- type: Documentation
  url: https://docs.sleeper.com/
- type: APIReference
  url: https://docs.sleeper.com/
- type: SignUp
  url: https://sleeper.com/
- type: Support
  url: https://support.sleeper.com/
- type: Blog
  url: https://blog.sleeper.com/
- type: TermsOfService
  url: https://sleeper.com/terms
- type: PrivacyPolicy
  url: https://sleeper.com/privacy
- type: Authentication
  url: authentication/sleeper-authentication.yml
- type: ErrorCatalog
  url: errors/sleeper-problem-types.yml
- type: Conventions
  url: conventions/sleeper-conventions.yml
- type: DataModel
  url: data-model/sleeper-data-model.yml
- type: X-MCPServerCandidate
  url: mcp/sleeper-mcp.yml
  note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list derived
    from the published API contracts, not an existing server. The scorer already read the manifest and reported mcp_server
    correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
- type: LLMsTxt
  url: llms/sleeper-llms.txt
- type: Overlay
  url: overlays/sleeper-openapi-overlay.yaml
- type: Conformance
  url: conformance/sleeper-conformance.yml
- type: Lifecycle
  url: lifecycle/sleeper-lifecycle.yml
- type: WellKnown
  url: well-known/sleeper-well-known.yml
- type: Packages
  url: packages/sleeper-packages.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-21'
  status: enriched
  artifacts_added: 16
  pass: local-v1
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io

Sleeper API — frequently asked questions

Does Sleeper have an API?

Yes. APIs.io lists 8 APIs from Sleeper, including Sleeper Drafts API, Sleeper Leagues API and Sleeper Matchups API, and 5 more.

Is there an OpenAPI specification for the Sleeper API?

Yes. APIs.io indexes 8 OpenAPI specifications for Sleeper, each linked for download from this page.

How do I authenticate with the Sleeper API?

Sleeper uses bearer-token authentication (none · 0 schemes). The details are profiled on APIs.io as Sleeper Authentication.

Is the Sleeper API ready for AI agents?

Sleeper has a Kin Score of 30.2 out of 100 (thin) and an Agent Readiness score of 20.9 (agent-aware), scored by API Evangelist on 2026-11-06.

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