Mastodon Instances website screenshot

Mastodon Instances

Mastodon Instances (instances.social) is a service for discovering Mastodon server instances. Its API allows developers to search for instances by criteria including language, user count, and stability, and to retrieve metadata about specific instances.

Mastodon Instances publishes 2 APIs on the APIs.io network: Instances API and Versions API. Tagged areas include Fediverse, Mastodon, Search, and Social.

Mastodon Instances’ developer surface includes authentication, developer portal, signup flow, and 2 more developer resources.

🌐 Visit website 📡 Source on GitHub
36.8/100 thin ▬ flat Agent 31/100 agent aware Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1
AccessFreemiumSelf serve⚡ Free to try
3 APIs
FediverseMastodonSearchSocial

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1
Composite quality — 36.8/100 · thin
Contract Quality 14.4 / 25
Developer Ergonomics 3.9 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 4.1 / 13
Governance 0.0 / 12
Discoverability 6.5 / 10
Agent readiness — 31/100 · agent aware
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/mastodon-instances: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 3

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

Mastodon Instances API

The instances.social API allows searching for and retrieving information about Mastodon server instances, including user counts, language, software version, and uptime statistics.

Mastodon Instances Instances API

The Instances API from Mastodon Instances — 4 operation(s) for instances.

Mastodon Instances Versions API

The Versions API from Mastodon Instances — 2 operation(s) for versions.

Open Collections 1

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

Mastodon Instances API

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Mastodon Instances Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Mastodon Instances Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Mastodon Instances Finops

FINOPS

Security Posture 2

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

Mastodon Instances Authentication

http · 1 scheme

SECURITY

Mastodon Instances Domain Security

TLSv1.3 · HSTS · DNSSEC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Mastodon Instances Agentic Access

6 operations

6 operations · 0 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

Portal
Portal
 Signup
Signup

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity
 Authentication
Authentication

Source (apis.yml)

apis.yml Raw ↑ 
aid: mastodon-instances
name: Mastodon Instances
description: Mastodon Instances (instances.social) is a service for discovering Mastodon server instances. Its API allows
  developers to search for instances by criteria including language, user count, and stability, and to retrieve metadata about
  specific instances.
type: Index
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/mastodon-instances.png
url: https://raw.githubusercontent.com/api-evangelist/mastodon-instances/refs/heads/main/apis.yml
tags:
- Fediverse
- Mastodon
- Search
- Social
created: '2024-12-02'
modified: '2026-04-28'
specificationVersion: '0.19'
apis:
- aid: mastodon-instances:mastodon-instances
  name: Mastodon Instances API
  tags:
  - Mastodon
  - Search
  - Social
  humanURL: https://instances.social
  baseURL: https://instances.social/api
  properties:
  - url: https://instances.social/api/doc/
    type: Documentation
  description: The instances.social API allows searching for and retrieving information about Mastodon server instances, including
    user counts, language, software version, and uptime statistics.
- aid: mastodon-instances:mastodon-instances-instances-api
  name: Mastodon Instances Instances API
  description: The Instances API from Mastodon Instances — 4 operation(s) for instances.
  humanURL: https://instances.social
  baseURL: https://instances.social/api
  tags:
  - Instances
  properties:
  - type: OpenAPI
    url: openapi/mastodon-instances-instances-api-openapi.yml
- aid: mastodon-instances:mastodon-instances-versions-api
  name: Mastodon Instances Versions API
  description: The Versions API from Mastodon Instances — 2 operation(s) for versions.
  humanURL: https://instances.social
  baseURL: https://instances.social/api
  tags:
  - Versions
  properties:
  - type: OpenAPI
    url: openapi/mastodon-instances-versions-api-openapi.yml
common:
- type: AgenticAccess
  url: agentic-access/mastodon-instances-agentic-access.yml
- type: DomainSecurity
  url: security/mastodon-instances-domain-security.yml
- type: Authentication
  url: authentication/mastodon-instances-authentication.yml
- type: Portal
  url: https://instances.social
- type: Signup
  url: https://instances.social/api/token
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com