Buttondown
Buttondown is an independent, bootstrapped email newsletter platform for writers, creators and developers, offering a Markdown and rich-text editor, subscriber management with tags, segments and metadata, automations, RSS-to-email, surveys, comments, paid subscriptions via Stripe with no revenue share, custom sending and hosting domains, and hosted archives. Its public REST API covers 133 operations across 29 resource areas — subscribers, emails, tags, segments, automations, webhooks, imports, exports, surveys, forms, images, snippets, prices and more — described by a live OpenAPI 3.1 document, backed by an 82-event webhook catalog, a date-based version train, idempotency keys, and a first-party CLI for syncing newsletter content to a local folder.
Reference-quality API operations across every facet — a rich contract, published governance, transparent operations, and machine-readable commercial terms.
API Evangelist profiles Buttondown the way a machine reads it — 71 machine-readable artifacts across 1 API, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Buttondown scores 67.3/100 (exemplar), with a separate agent-readiness read of 39/100 (agent native). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-10 · rubric v0.20.0
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How we profile Buttondown
Each block below is one kind of artifact we hold for Buttondown. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 31
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Buttondown Accounts API
The Accounts API from Buttondown — 1 operation(s) covering the authenticated account and its plan/feature state.
Buttondown Advertising Units API
The Advertising Units API from Buttondown — 6 operation(s) covering newsletter sponsorship inventory — advertising units and the slots sold against them.
Buttondown API Requests API
The API Requests API from Buttondown — 2 operation(s) covering the account's own API request log, including retained response bodies for idempotent requests.
Buttondown Attachments API
The Attachments API from Buttondown — 4 operation(s) covering files attached to emails and inbox replies.
Buttondown Automations API
The Automations API from Buttondown — 7 operation(s) covering triggered and scheduled email sequences, their actions, timing and analytics.
Buttondown Books API
The Books API from Buttondown — 5 operation(s) covering the Bookshop.org book catalog embedded in newsletters.
Buttondown Bulk Actions API
The Bulk Actions API from Buttondown — 2 operation(s) covering asynchronous mass operations over existing records.
Buttondown Comments API
The Comments API from Buttondown — 5 operation(s) covering subscriber comments on emails, and their moderation state.
Buttondown Coupons API
The Coupons API from Buttondown — 1 operation(s) covering Stripe coupons available to a paid newsletter.
Buttondown Emails API
The Emails API from Buttondown — 11 operation(s) covering drafting, scheduling, publishing, rendering and analyzing newsletter emails.
Buttondown Events API
The Events API from Buttondown — 2 operation(s) covering the unified event store that also powers webhooks.
Buttondown Exports API
The Exports API from Buttondown — 3 operation(s) covering data exports of subscribers, emails and events.
Buttondown External Feeds API
The External Feeds API from Buttondown — 7 operation(s) covering RSS-to-email feeds, their polling cadence and the items they produce.
Buttondown Forms API
The Forms API from Buttondown — 5 operation(s) covering hosted and embeddable subscription forms.
Buttondown Images API
The Images API from Buttondown — 4 operation(s) covering images hosted for use in emails and archives.
Buttondown Imports API
The Imports API from Buttondown — 5 operation(s) covering bulk subscriber imports — the supported path for adding subscribers at volume.
Buttondown Newsletters API
The Newsletters API from Buttondown — 7 operation(s) covering newsletter settings, branding, locale, and custom sending/hosting domain verification.
Buttondown Notes API
The Notes API from Buttondown — 3 operation(s) covering internal notes attached to subscribers and team members.
Buttondown Ping API
The Ping API from Buttondown — 1 operation(s) covering a connectivity and credential health check.
Buttondown Prices API
The Prices API from Buttondown — 3 operation(s) covering paid-subscription pricing and products.
Buttondown Public API
The Public API from Buttondown — 1 operation(s) covering the unauthenticated public archive search.
Buttondown Segments API
The Segments API from Buttondown — 5 operation(s) covering saved, reusable audiences built from tag and metadata filters.
Buttondown Snippets API
The Snippets API from Buttondown — 5 operation(s) covering reusable content snippets referenced from emails.
Buttondown Subscribers API
The Subscribers API from Buttondown — 12 operation(s) covering subscriber lifecycle — creation, updates, tags, referrals, automations and Stripe subscriptions.
Buttondown Survey Responses API
The Survey Responses API from Buttondown — 3 operation(s) covering responses collected from newsletter surveys.
Buttondown Surveys API
The Surveys API from Buttondown — 5 operation(s) covering surveys embedded in emails and on the archive.
Buttondown Tags API
The Tags API from Buttondown — 6 operation(s) covering subscriber tags and their analytics.
Buttondown Users API
The Users API from Buttondown — 5 operation(s) covering team members on the account and their permissions.
Buttondown Webhooks API
The Webhooks API from Buttondown — 7 operation(s) covering webhook registration, delivery attempts, and test fires.
Buttondown Newsletter Platform
The Buttondown hosted newsletter platform provides a markdown-based composition experience, subscriber management, delivery infrastructure, analytics, monetization via paid subs...
Buttondown Buttondown Webhooks API
The Buttondown Webhooks API API from Buttondown — 0 operation(s) for buttondown webhooks api.
Scroll within the panel for all 31 ·
Open Collections 30
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Buttondown Accounts API
OPEN COLLECTIONButtondown Advertising Units API
OPEN COLLECTIONButtondown API Requests API
OPEN COLLECTIONButtondown Attachments API
OPEN COLLECTIONButtondown Automations API
OPEN COLLECTIONButtondown Books API
OPEN COLLECTIONButtondown Bulk Actions API
OPEN COLLECTIONButtondown Comments API
OPEN COLLECTIONButtondown Coupons API
OPEN COLLECTIONButtondown Emails API
OPEN COLLECTIONButtondown Events API
OPEN COLLECTIONButtondown Exports API
OPEN COLLECTIONButtondown External Feeds API
OPEN COLLECTIONButtondown Forms API
OPEN COLLECTIONButtondown Images API
OPEN COLLECTIONButtondown Imports API
OPEN COLLECTIONButtondown Newsletters API
OPEN COLLECTIONButtondown Notes API
OPEN COLLECTIONButtondown Ping API
OPEN COLLECTIONButtondown Prices API
OPEN COLLECTIONButtondown public API
OPEN COLLECTIONButtondown Segments API
OPEN COLLECTIONButtondown Snippets API
OPEN COLLECTIONButtondown Subscribers API
OPEN COLLECTIONButtondown Survey Responses API
OPEN COLLECTIONButtondown Surveys API
OPEN COLLECTIONButtondown Tags API
OPEN COLLECTIONButtondown Users API
OPEN COLLECTIONButtondown Webhooks API
OPEN COLLECTIONButtondown API
OPEN COLLECTIONScroll within the panel for all 30 ·
Pricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the things the Kin Score reads for access clarity — renamed from commercial clarity in rubric 0.12, because a free statutory interface has access terms and no commercial ones.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Buttondown Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Buttondown Finops
FINOPSEvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Buttondown Webhooks
ASYNCAPIExamples 2
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Buttondown Enums
EXAMPLEButtondown Fixtures
EXAMPLESecurity Posture 3
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Buttondown — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 5
Portal, sign-up, and the first successful call
Documentation 3
Reference material describing how the API behaves
Agent Surfaces 4
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 9
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 9 ·
Build 5
SDKs, sample code, and the tooling you integrate with
Access & Security 6
Authentication, authorization, and security posture
Operate 5
Status, limits, changes, and where to get help
Commercial 5
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
Other 1
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/buttondown · machine-readable index on apis.io
This is an independent, third-party profile of Buttondown, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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