Plain

Plain is an API-first customer support platform built around a single GraphQL API. Everything in the product - customers, threads, timeline entries, messages, labels, tiers, and webhooks - is exposed through the same GraphQL endpoint the Plain UI consumes, letting teams build support into their own products with threads, customer context, and a unified timeline.

Plain publishes 1 API on the APIs.io network: GraphQL API. Tagged areas include Customer-Support, Help Desk, GraphQL, Threads, and Customer Communication.

Plain’s developer surface includes authentication, documentation, engineering blog, and 8 more developer resources.

🌐 Visit website 📡 Source on GitHub

39.9/100 developing ▬ flat Agent 25/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessFreemiumOpenFree trial⚡ Free to try

1 APIs

Customer-Support Help Desk GraphQL Threads Customer Communication API-First

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 39.9/100 · developing

Contract Quality 13.7 / 23

Developer Ergonomics 5.6 / 18

Access Clarity 7.1 / 18

Operational Transparency 4.0 / 12

Contract Governance 0.0 / 11

Discoverability 6.2 / 9

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 25/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 7 / 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

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

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/plain-support: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 1

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

Plain GraphQL API

The GraphQL API from Plain — 1 operation(s) for graphql.

Open Collections 3

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

API Collection

OPEN COLLECTION

Plain GraphQL API

OPEN COLLECTION

Plain GraphQL API

OPEN COLLECTION

GraphQL 1

GraphQL schemas published by this provider.

Plain GraphQL API

Representative GraphQL schema for the [Plain](https://www.plain.com/) API-first customer

GRAPHQL

Pricing Plans 1

Published pricing tiers and plan structures.

Plain Support Plans Pricing

4 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Plain Support Rate Limits

3 limits

RATE LIMITS

FinOps 1

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

Plain Support Finops

FINOPS

Security Posture 2

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

Plain Support Authentication

http · 1 scheme

SECURITY

Plain Support Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

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

Plain Support Agentic Access

1 operation · 1 acting

1 operations · 1 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 1

Status, limits, changes, and where to get help

RateLimits

RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

FinOps

FinOps

Company 3

The organization behind the API

LinkedIn

Website

Website

Blog

Blog

Source (apis.yml)

aid: plain-support
url: https://raw.githubusercontent.com/api-evangelist/plain-support/refs/heads/main/apis.yml
name: Plain
kind: company
description: Plain is an API-first customer support platform built around a single GraphQL API. Everything in the product
  - customers, threads, timeline entries, messages, labels, tiers, and webhooks - is exposed through the same GraphQL endpoint
  the Plain UI consumes, letting teams build support into their own products with threads, customer context, and a unified
  timeline.
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: freemium
  onboarding: open
  trial: true
  try_now: true
  public: true
  label: Freemium (free trial) · Open access
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/plain-support.png
tags:
- Customer-Support
- Help Desk
- GraphQL
- Threads
- Customer Communication
- API-First
tags_raw:
- Customer Support
- Help Desk
- GraphQL
- Threads
- Customer Communication
- API First
created: '2026-06-20'
modified: '2026-06-20'
specificationVersion: '0.23'
apis:
- aid: plain-support:plain-support-graphql-api
  name: Plain GraphQL API
  description: The GraphQL API from Plain — 1 operation(s) for graphql.
  humanURL: https://www.plain.com/docs/api-reference/graphql/customers/upserting-customers
  baseURL: https://core-api.uk.plain.com/graphql/v1
  tags:
  - GraphQL
  properties:
  - type: OpenAPI
    url: openapi/plain-support-graphql-api-openapi.yml
  - type: GraphQL
    url: graphql/plain-support-graphql.md
  - type: Documentation
    url: https://www.plain.com/docs/api-reference/graphql/customers/upserting-customers
  - type: APIReference
    url: https://www.plain.com/docs/api-reference/graphql/introduction
  - type: Documentation
    url: https://www.plain.com/docs/api-reference/graphql/threads/create-threads
  - type: Documentation
    url: https://www.plain.com/docs/api-reference/graphql/events/create-a-thread-event
  - type: Documentation
    url: https://www.plain.com/docs/api-reference/graphql/messages/reply-to-threads
  - type: Documentation
    url: https://www.plain.com/docs/api-reference/graphql/labels/add-labels
  - type: Documentation
    url: https://www.plain.com/docs/api-reference/graphql/webhooks/create-a-webhook-target
common:
- type: AgenticAccess
  url: agentic-access/plain-support-agentic-access.yml
- type: DomainSecurity
  url: security/plain-support-domain-security.yml
- type: Authentication
  url: authentication/plain-support-authentication.yml
- type: GitHubOrganization
  url: https://github.com/team-plain
- type: LinkedIn
  url: https://www.linkedin.com/company/plain-support
- type: Website
  url: https://www.plain.com
- type: Documentation
  url: https://www.plain.com/docs
- type: Plans
  url: plans/plain-support-plans-pricing.yml
- type: RateLimits
  url: rate-limits/plain-support-rate-limits.yml
- type: FinOps
  url: finops/plain-support-finops.yml
- url: https://www.plain.com/blog
  type: Blog
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/plain-support"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/plain-support/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/plain-support/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.