Matter

Matter is a modern read-later application for people who take reading seriously — save articles, newsletters, podcasts, PDFs, and tweets from anywhere and read them in a clean, focused interface on iOS and the web, with highlighting, notes, tags, offline search, text-to-speech, and audio transcription of podcasts and videos. For Matter Pro subscribers, Matter ships a public REST API (api.getmatter.com/public/v1) to save, organize, search, and incrementally sync a reading library, secured with a personal Bearer token. It is complemented by a first-party CLI/TUI and official Obsidian, Roam, and Logseq highlight-export integrations. Matter is backed by GV (Google Ventures).

Matter publishes 6 API contracts indexed on the APIs.io network, including Account API, Annotations API, Items API, and 3 more. Tagged areas include Company, Consumer, Reading, Read Later, and Productivity.

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

Matter’s developer surface includes documentation, API reference, getting-started guide, authentication, CLI, support, signup flow, and 24 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

54.3/100 strong ▬ flat Agent 33/100 agent ready Front door AI 1/6 silent Heartbeat 24/100 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 Consumer ReadingRead LaterProductivity Content Highlights Bookmarking

Kin Score

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

Composite quality — 54.3/100 · strong

Contract Quality 11.8 / 19

Developer Ergonomics 9.6 / 15

Access Clarity 5.1 / 15

Operational Transparency 5.1 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 4.6 / 15

Create-or-Update Ergonomics 1.1 / 10

Agent readiness — 33/100 · agent ready

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 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 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 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

Pagination 5 / 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 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.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% 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
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks

6 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 34.2 — up to +13.2 composite points
Contract Governance scores 18.2 — up to +9.8 composite points
Contract Quality scores 62.9 — up to +9.3 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/matter/apis.yml: open an issue on github.com/api-evangelist/matter 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 →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Raycast Store Extensions (first-party publishers + community-wrapped products)	covered	9.6 (thin)	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

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 6

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

Matter Account API

Your user profile and API quota.

Matter Annotations API

Highlights and notes on items.

Matter Items API

Articles, podcasts, videos, PDFs, and tweets in your library.

Matter Reading Sessions API

Reading time history.

Matter Search API

Full-text search across Matter.

Matter Tags API

Labels for organizing items.

Open Collections 6

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

Matter Account API

OPEN COLLECTION

Matter Account Annotations API

OPEN COLLECTION

Matter Account Items API

OPEN COLLECTION

Matter Account Reading Sessions API

OPEN COLLECTION

Matter Account Search API

OPEN COLLECTION

Matter Account Tags API

OPEN COLLECTION

Agent Skills 3

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

Save and organize an article in Matter

AGENT SKILL

Search Matter and read an item with its highlights

AGENT SKILL

Incrementally sync a Matter library

AGENT SKILL

Matter API pricing

Rate limits

Read: 120 requests per minute
Write: 30 requests per minute
Save: 10 requests per minute

All 6 limits →

Rate Limits 1

Documented rate limits and quota policies.

Matter Rate Limits

6 limits

RATE LIMITS

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Matter API Rules

66 rules · 64 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.

Matter Openapi Overlay

3 actions · update · matter-openapi-original.yml

DERIVED

Security Posture 3

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

Matter Authentication

http · 1 scheme

SECURITY

Matter Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Matter Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

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

Matter Agentic Access

17 operations · 9 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

SignUp

SignUp

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

X-MCPServerCandidate

AgentSkill

AgenticAccess

LLMsTxt

WellKnown

Design & Contract 5

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Lifecycle

DataModel

Conformance

Build 3

SDKs, sample code, and the tooling you integrate with

Packages

Packages

CLI

CLI

GitHubOrganization

GitHubOrganization

Access & Security 5

Authentication, authorization, and security posture

Authentication

Authentication

SecurityTxt

SecurityTxt

VulnerabilityDisclosure

VulnerabilityDisclosure

Security

Security

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

RateLimits

RateLimits

Deprecation

Deprecation

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 1

The organization behind the API

Website

Website

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

Source (apis.yml)

aid: matter
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
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/matter.png
name: Matter
description: Matter is a modern read-later application for people who take reading seriously — save articles, newsletters,
  podcasts, PDFs, and tweets from anywhere and read them in a clean, focused interface on iOS and the web, with highlighting,
  notes, tags, offline search, text-to-speech, and audio transcription of podcasts and videos. For Matter Pro subscribers,
  Matter ships a public REST API (api.getmatter.com/public/v1) to save, organize, search, and incrementally sync a reading
  library, secured with a personal Bearer token. It is complemented by a first-party CLI/TUI and official Obsidian, Roam,
  and Logseq highlight-export integrations. Matter is backed by GV (Google Ventures).
url: https://raw.githubusercontent.com/api-evangelist/matter/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- gv
x-tier: profiled
x-tier-reason: enriched-2026-07-20
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-04
x-docs-hosting: vercel
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 22
  pass: local-v1
tags:
- Company
- Consumer
- Reading
- Read Later
- Productivity
- Content
- Highlights
- Bookmarking
apis:
- aid: matter:matter-account-api
  name: Matter Account API
  description: Your user profile and API quota.
  humanURL: https://docs.getmatter.com/api
  baseURL: https://api.getmatter.com/public/v1
  tags:
  - Account
  properties:
  - type: OpenAPI
    url: openapi/matter-account-api-openapi.yml
  - type: Documentation
    url: https://docs.getmatter.com/api
  - type: APIReference
    url: https://docs.getmatter.com/api
  - type: Authentication
    url: https://docs.getmatter.com/api/authentication
- aid: matter:matter-annotations-api
  name: Matter Annotations API
  description: Highlights and notes on items.
  humanURL: https://docs.getmatter.com/api
  baseURL: https://api.getmatter.com/public/v1
  tags:
  - Annotation
  tags_raw:
  - Annotations
  properties:
  - type: OpenAPI
    url: openapi/matter-annotations-api-openapi.yml
  - type: Documentation
    url: https://docs.getmatter.com/api
  - type: APIReference
    url: https://docs.getmatter.com/api
  - type: Authentication
    url: https://docs.getmatter.com/api/authentication
- aid: matter:matter-items-api
  name: Matter Items API
  description: Articles, podcasts, videos, PDFs, and tweets in your library.
  humanURL: https://docs.getmatter.com/api
  baseURL: https://api.getmatter.com/public/v1
  tags:
  - Item
  tags_raw:
  - Items
  properties:
  - type: OpenAPI
    url: openapi/matter-items-api-openapi.yml
  - type: Documentation
    url: https://docs.getmatter.com/api
  - type: APIReference
    url: https://docs.getmatter.com/api
  - type: Authentication
    url: https://docs.getmatter.com/api/authentication
- aid: matter:matter-reading-sessions-api
  name: Matter Reading Sessions API
  description: Reading time history.
  humanURL: https://docs.getmatter.com/api
  baseURL: https://api.getmatter.com/public/v1
  tags:
  - Reading Sessions
  properties:
  - type: OpenAPI
    url: openapi/matter-reading-sessions-api-openapi.yml
  - type: Documentation
    url: https://docs.getmatter.com/api
  - type: APIReference
    url: https://docs.getmatter.com/api
  - type: Authentication
    url: https://docs.getmatter.com/api/authentication
- aid: matter:matter-search-api
  name: Matter Search API
  description: Full-text search across Matter.
  humanURL: https://docs.getmatter.com/api
  baseURL: https://api.getmatter.com/public/v1
  tags:
  - Search
  properties:
  - type: OpenAPI
    url: openapi/matter-search-api-openapi.yml
  - type: Documentation
    url: https://docs.getmatter.com/api
  - type: APIReference
    url: https://docs.getmatter.com/api
  - type: Authentication
    url: https://docs.getmatter.com/api/authentication
- aid: matter:matter-tags-api
  name: Matter Tags API
  description: Labels for organizing items.
  humanURL: https://docs.getmatter.com/api
  baseURL: https://api.getmatter.com/public/v1
  tags:
  - Tags
  properties:
  - type: OpenAPI
    url: openapi/matter-tags-api-openapi.yml
  - type: Documentation
    url: https://docs.getmatter.com/api
  - type: APIReference
    url: https://docs.getmatter.com/api
  - type: Authentication
    url: https://docs.getmatter.com/api/authentication
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Overlay
  url: overlays/matter-openapi-overlay.yaml
- type: DeveloperPortal
  url: https://docs.getmatter.com
- type: Documentation
  url: https://docs.getmatter.com/api
- type: APIReference
  url: https://docs.getmatter.com/api
- type: GettingStarted
  url: https://docs.getmatter.com/api/quickstart
- type: Authentication
  url: authentication/matter-authentication.yml
- type: Conventions
  url: conventions/matter-conventions.yml
- type: ErrorCatalog
  url: errors/matter-problem-types.yml
- type: RateLimits
  url: rate-limits/matter-rate-limits.yml
- type: Lifecycle
  url: lifecycle/matter-lifecycle.yml
- type: Deprecation
  url: lifecycle/matter-lifecycle.yml
- type: DataModel
  url: data-model/matter-data-model.yml
- type: Conformance
  url: conformance/matter-conformance.yml
- type: Packages
  url: packages/matter-packages.yml
- type: CLI
  url: cli/matter-cli.yml
- type: X-MCPServerCandidate
  url: mcp/matter-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: AgentSkill
  url: skills/_index.yml
- type: AgenticAccess
  url: agentic-access/matter-agentic-access.yml
- type: LLMsTxt
  url: llms/matter-llms.txt
- type: WellKnown
  url: well-known/matter-well-known.yml
- type: SecurityTxt
  url: well-known/matter-security.txt
- type: VulnerabilityDisclosure
  url: security/matter-vulnerability-disclosure.yml
- type: Security
  url: security/matter-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/matter-domain-security.yml
- type: GitHubOrganization
  url: https://github.com/getmatterapp
- type: Support
  url: mailto:hello@getmatter.com
- type: SignUp
  url: https://web.getmatter.com
- type: Login
  url: https://web.getmatter.com
- type: TermsOfService
  url: https://www.getmatter.com/terms
- type: PrivacyPolicy
  url: https://www.getmatter.com/privacy
- type: Website
  url: https://www.getmatter.com

Matter API — frequently asked questions

Does Matter have an API?

Yes. APIs.io lists 6 APIs from Matter, including Matter Account API, Matter Annotations API and Matter Items API, and 3 more.

Is there an OpenAPI specification for the Matter API?

Yes. APIs.io indexes 6 OpenAPI specifications for Matter, each linked for download from this page.

How do I authenticate with the Matter API?

Matter uses bearer-token authentication (http · 1 scheme). The details are profiled on APIs.io as Matter Authentication.

Is the Matter API ready for AI agents?

Matter has a Kin Score of 54.3 out of 100 (strong) and an Agent Readiness score of 32.6 (agent-ready), scored by API Evangelist on 2026-11-06.

Work with this as data

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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.

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Every operation they expose

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curl "https://apis.io/api/v1/providers/matter/evidence"

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