Substack is an independent newsletter and media platform that lets writers, podcasters, video creators, and other culture makers publish directly to readers and monetize through paid subscriptions. Founded in 2017 by Chris Best (CEO), Jairaj Sethi (CTO), and Hamish McKenzie (CWO) and headquartered in San Francisco with a New York City office, Substack provides built-in subscription billing, paid posts, podcasting, chat, video, Notes, and a cross-publication recommendations network. Creators keep 90 percent of subscription revenue (less credit card fees) and own their mailing lists and content. The platform reports more than five million paid subscriptions and tens of millions of weekly active readers. Substack does not offer a general-purpose public REST API for managing publications, posts, or subscribers. It does publish a narrowly scoped official Developer API (released April 2026) that allows token-authenticated lookup of public Substack profiles by LinkedIn handle, gated by an application and Terms-of-Use process. Substack also runs an official remote MCP server at https://mcp.substack.com/api/v1/mcp, documented August 2026, which gives an MCP-capable AI assistant read-only access to publication analytics under OAuth 2.1 with the mcp:read scope, gated to Admins of Bestseller publications. Read access to public content is otherwise available via per-publication RSS feeds, and the broader integration ecosystem relies on reverse-engineered, unofficial JSON endpoints used by the Substack web application. Substack publishes no OpenAPI, no AsyncAPI, no webhooks and no first-party SDK in any package registry.
Substack publishes 3 APIs on the APIs.io network. Tagged areas include Newsletters, Publishing, Creator Economy, Subscription, and Email.
Substack’s developer surface includes authentication, changelog, documentation, support, engineering blog, pricing, signup flow, and 33 more developer resources.
Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for
this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero:
never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and
several others — scorable at all.
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 github.com/api-evangelist/substack: open an issue to ask a question, or submit a pull request to add artifacts.
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Narrowly scoped official API that returns public Substack profile data for a given LinkedIn handle. Access requires accepting the Developer API Terms of Use, applying via form, ...
Official remote Model Context Protocol server that connects a Substack publication to an MCP-capable AI assistant (Claude, ChatGPT, Cursor). Read-only: it serves publication das...
Per-publication public RSS feeds available at https://{publication}.substack.com/feed for syndication and read-only access to posts. RSS 2.0 with the content, dc, atom and itune...
aid: substack
name: Substack
description: Substack is an independent newsletter and media platform that lets writers, podcasters, video creators, and other
culture makers publish directly to readers and monetize through paid subscriptions. Founded in 2017 by Chris Best (CEO),
Jairaj Sethi (CTO), and Hamish McKenzie (CWO) and headquartered in San Francisco with a New York City office, Substack provides
built-in subscription billing, paid posts, podcasting, chat, video, Notes, and a cross-publication recommendations network.
Creators keep 90 percent of subscription revenue (less credit card fees) and own their mailing lists and content. The platform
reports more than five million paid subscriptions and tens of millions of weekly active readers. Substack does not offer
a general-purpose public REST API for managing publications, posts, or subscribers. It does publish a narrowly scoped official
Developer API (released April 2026) that allows token-authenticated lookup of public Substack profiles by LinkedIn handle,
gated by an application and Terms-of-Use process. Substack also runs an official remote MCP server at https://mcp.substack.com/api/v1/mcp,
documented August 2026, which gives an MCP-capable AI assistant read-only access to publication analytics under OAuth 2.1
with the mcp:read scope, gated to Admins of Bestseller publications. Read access to public content is otherwise available
via per-publication RSS feeds, and the broader integration ecosystem relies on reverse-engineered, unofficial JSON endpoints
used by the Substack web application. Substack publishes no OpenAPI, no AsyncAPI, no webhooks and no first-party SDK in
any package registry.
type: Index
deliveryModel:
model: saas
open_source: false
commercial: true
callable_host: false
label: Hosted service · you call their endpoint
confidence: medium
source:
- pricing
generated: '2026-08-28'
method: derived
accessModel:
pricing: unknown
onboarding: unknown
trial: false
try_now: false
public: false
label: Unknown
confidence: low
source: []
generated: '2026-07-22'
method: derived
position: Producing
access: 3rd-Party
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/substack.png
tags:
- Newsletters
- Publishing
- Creator Economy
- Subscription
- Email
- Podcasting
- Notes
- Media
- Independent Media
- Paid Content
- MCP
- Agents
- RSS
- Analytics
tags_raw:
- Newsletters
- Publishing
- Creator Economy
- Subscriptions
- Email
- Podcasting
- Notes
- Media
- Independent Media
- Paid Content
- MCP
- Agents
- RSS
- Analytics
url: https://raw.githubusercontent.com/api-evangelist/substack/refs/heads/main/apis.yml
created: '2026-05-08'
modified: '2026-08-13'
specificationVersion: '0.23'
apis:
- name: Substack Developer API
description: Narrowly scoped official API that returns public Substack profile data for a given LinkedIn handle. Access
requires accepting the Developer API Terms of Use, applying via form, and generating a token from the Developer API section
of account settings. Only profiles meeting Substack's authenticity thresholds are returned.
humanURL: https://support.substack.com/hc/en-us/articles/45099095296916-Substack-Developer-API
baseURL: https://substack.com
tags:
- Profile
- LinkedIn
- Read Only
- Gated
tags_raw:
- Profile
- LinkedIn
- Read-Only
- Gated
properties:
- type: Documentation
url: https://support.substack.com/hc/en-us/articles/45099095296916-Substack-Developer-API
- type: APIReference
url: https://support.substack.com/hc/en-us/articles/45099095296916-Substack-Developer-API
- type: TermsOfService
name: Substack Developer API Terms of Use
url: https://substack.com/api-tos
- type: Authentication
url: authentication/substack-authentication.yml
- name: Substack MCP Server
description: 'Official remote Model Context Protocol server that connects a Substack publication to an MCP-capable AI assistant
(Claude, ChatGPT, Cursor). Read-only: it serves publication dashboard metrics, subscriber counts, revenue, post performance,
traffic sources, retention and publication settings. It cannot publish posts, send Notes or modify the account, and cannot
read profile or Notes activity. Authorization is OAuth 2.1 authorization-code with PKCE S256 against https://substack.com,
scope mcp:read, with RFC 9728 protected resource metadata advertised in the endpoint''s own 401 challenge. Connecting
requires Admin role on a Bestseller publication.'
humanURL: https://support.substack.com/hc/en-us/articles/50834026608916-How-to-connect-Substack-to-your-AI-Assistant
baseURL: https://mcp.substack.com/api/v1/mcp
tags:
- MCP
- Agents
- Analytics
- Read Only
- Authentication
tags_raw:
- MCP
- Agents
- Analytics
- Read-Only
- OAuth
properties:
- type: MCPServer
url: mcp/substack-mcp.yml
- type: Documentation
url: https://support.substack.com/hc/en-us/articles/50834026608916-How-to-connect-Substack-to-your-AI-Assistant
- type: GettingStarted
url: https://support.substack.com/hc/en-us/articles/50834026608916-How-to-connect-Substack-to-your-AI-Assistant
- type: Authentication
url: authentication/substack-authentication.yml
- type: OAuthScopes
url: scopes/substack-scopes.yml
- name: Substack RSS Feeds
description: Per-publication public RSS feeds available at https://{publication}.substack.com/feed for syndication and read-only
access to posts. RSS 2.0 with the content, dc, atom and itunes namespaces; no credential required. Podcast subscribers
additionally receive a private per-subscriber feed whose contents depend on their subscription tier.
humanURL: https://support.substack.com/hc/en-us/articles/360038239391-Is-there-an-RSS-feed-for-my-publication
baseURL: https://{publication}.substack.com
tags:
- RSS
- Read Only
- Syndication
tags_raw:
- RSS
- Read-Only
- Syndication
properties:
- type: Documentation
url: https://support.substack.com/hc/en-us/articles/360038239391-Is-there-an-RSS-feed-for-my-publication
- type: Documentation
name: Podcast RSS feeds and paid content
url: https://support.substack.com/hc/en-us/articles/360041722272-Will-my-Podcast-RSS-feed-show-paid-only-content
common:
- type: VulnerabilityDisclosure
url: security/substack-vulnerability-disclosure.yml
- type: DomainSecurity
url: security/substack-domain-security.yml
- type: Security
name: Substack Vulnerability Disclosure Policy
url: https://substack.com/vulnerability-disclosure
- type: MCPServer
url: mcp/substack-mcp.yml
- type: WellKnown
url: well-known/substack-well-known.yml
- type: Authentication
url: authentication/substack-authentication.yml
- type: OAuthScopes
url: scopes/substack-scopes.yml
- type: Conformance
url: conformance/substack-conformance.yml
- type: ErrorCatalog
url: errors/substack-problem-types.yml
- type: Conventions
url: conventions/substack-conventions.yml
- type: Lifecycle
url: lifecycle/substack-lifecycle.yml
- type: StatusPage
url: https://status.substack.com/
- type: ChangeLog
url: changelog/substack-changelog.yml
- type: RateLimits
url: rate-limits/substack-rate-limits.yml
- type: Plans
url: plans/substack-plans-pricing.yml
- type: Packages
url: packages/substack-packages.yml
- type: Components
url: components/substack-components.yml
- type: LLMsTxt
url: llms/substack-llms.txt
- type: Website
url: https://substack.com/
- type: About
url: https://substack.com/about
- type: Help
url: https://support.substack.com/
- type: Documentation
name: Substack Help Center
url: https://support.substack.com/hc/en-us
- type: Support
url: https://support.substack.com/hc/en-us/articles/43904995414164-How-to-contact-Substack-Support
- type: Blog
url: https://on.substack.com/
- type: BlogRSS
url: https://on.substack.com/feed
- type: Pricing
url: https://support.substack.com/hc/en-us/articles/360037607131-How-much-does-Substack-cost
- type: Pricing
name: Substack revenue calculator
url: https://substack.com/going-paid
- type: SignUp
url: https://substack.com/signup
- type: Login
url: https://substack.com/sign-in
- type: Jobs
url: https://substack.com/jobs
- type: Contact
url: https://substack.com/contact
- type: TermsOfService
url: https://substack.com/tos
- type: PrivacyPolicy
url: https://substack.com/privacy
- type: ContentGuidelines
url: https://substack.com/content
- type: Accessibility
url: https://substack.com/accessibility
- type: Sitemap
url: https://substack.com/sitemap
- type: BrandAssets
url: https://substack.com/brand
- type: GitHubOrganization
url: https://github.com/substackinc
- type: LinkedIn
url: https://www.linkedin.com/company/substack
- type: Twitter
url: https://twitter.com/SubstackInc
maintainers:
- FN: Kin Lane
email: kin@apievangelist.com
x-enrichment:
date: '2026-08-13'
status: enriched
artifacts_added: 17
pass: local-v1
x-coverage:
state: covered
reason: null
detail: 'Substack has a real, reachable agent surface — an official remote MCP server at https://mcp.substack.com/api/v1/mcp
with full RFC 8414 / RFC 9728 OAuth discovery — even though it publishes no OpenAPI. The one wall hit was documentation:
the Developer API reference article is linked from Substack''s own API Terms of Use but is absent from the public Help
Center index, its Zendesk API record returns 401, and support.substack.com answers non-browser clients with a Cloudflare
JavaScript challenge, so the Developer API''s exact auth header and error contract could not be read first-party.'
evidence:
- url: https://mcp.substack.com/api/v1/mcp
status: 401
- url: https://mcp.substack.com/.well-known/oauth-protected-resource/api/v1/mcp
status: 200
- url: https://substack.com/.well-known/oauth-authorization-server
status: 200
- url: https://support.substack.com/hc/en-us/articles/45099095296916-Substack-Developer-API
status: 403
- url: https://support.substack.com/api/v2/help_center/en-us/articles/45099095296916.json
status: 401
- url: https://substack.com/openapi.json
status: 404
checked: '2026-08-13'
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