Work with this as data
Every API 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 apis
7 MCP tools reach this
find_apisBrowse and filter every API in the catalog.get_api_artifactsOne API's artifacts, grouped by type.get_openapiThe primary OpenAPI for this API.find_similar_apisAPIs that look like this one.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.
Call it yourself
curl for this page
This API
curl "https://apis.io/api/v1/apis/matter-annotations-api"
All apis
curl "https://apis.io/api/v1/apis?limit=25"Discovery needs no key. Ratings and market analysis are Pro.
OpenAPI Specification
openapi: 3.2.0
info:
title: Matter Account Annotations API
version: '1.0'
description: 'The Matter API lets you read, save, and organize content in your Matter library.
Every request requires a [Bearer token](/api/authentication) and an active
Matter Pro subscription.
'
contact:
email: hello@getmatter.com
url: https://getmatter.com
servers:
- url: https://api.getmatter.com/public
description: Production
security:
- bearerAuth: []
tags:
- name: Annotations
description: Highlights and notes on items.
paths:
/v1/items/{item_id}/annotations:
parameters:
- name: item_id
in: path
required: true
description: The item ID (e.g. `itm_r9f3a`).
schema:
type: string
pattern: ^itm_[0-9A-Za-z]+$
get:
operationId: listAnnotations
summary: List annotations
description: Returns all annotations for a specific item.
tags:
- Annotations
parameters:
- $ref: '#/components/parameters/limit'
- $ref: '#/components/parameters/cursor'
responses:
'200':
description: Paginated list of annotations.
headers:
X-RateLimit-Limit:
$ref: '#/components/headers/X-RateLimit-Limit'
X-RateLimit-Remaining:
$ref: '#/components/headers/X-RateLimit-Remaining'
X-RateLimit-Reset:
$ref: '#/components/headers/X-RateLimit-Reset'
content:
application/json:
schema:
allOf:
- $ref: '#/components/schemas/PaginatedList'
- type: object
properties:
results:
type: array
items:
$ref: '#/components/schemas/Annotation'
'401':
$ref: '#/components/responses/Unauthorized'
'403':
$ref: '#/components/responses/ProRequired'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
/v1/annotations/{id}:
parameters:
- name: id
in: path
required: true
description: The annotation ID (e.g. `ann_m2k8v`).
schema:
type: string
pattern: ^ann_[0-9A-Za-z]+$
get:
operationId: getAnnotation
summary: Get annotation
description: Returns a single annotation.
tags:
- Annotations
responses:
'200':
description: Annotation detail.
headers:
X-RateLimit-Limit:
$ref: '#/components/headers/X-RateLimit-Limit'
X-RateLimit-Remaining:
$ref: '#/components/headers/X-RateLimit-Remaining'
X-RateLimit-Reset:
$ref: '#/components/headers/X-RateLimit-Reset'
content:
application/json:
schema:
$ref: '#/components/schemas/Annotation'
'401':
$ref: '#/components/responses/Unauthorized'
'403':
$ref: '#/components/responses/ProRequired'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
patch:
operationId: updateAnnotation
summary: Update annotation
description: Set or remove the note on an annotation.
tags:
- Annotations
requestBody:
required: true
content:
application/json:
schema:
type: object
required:
- note
properties:
note:
type: string
nullable: true
description: The note text. Pass `null` to remove the note.
responses:
'200':
description: Updated annotation.
headers:
X-RateLimit-Limit:
$ref: '#/components/headers/X-RateLimit-Limit'
X-RateLimit-Remaining:
$ref: '#/components/headers/X-RateLimit-Remaining'
X-RateLimit-Reset:
$ref: '#/components/headers/X-RateLimit-Reset'
content:
application/json:
schema:
$ref: '#/components/schemas/Annotation'
'401':
$ref: '#/components/responses/Unauthorized'
'403':
$ref: '#/components/responses/ProRequired'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
delete:
operationId: deleteAnnotation
summary: Delete annotation
description: Permanently delete an annotation.
tags:
- Annotations
responses:
'204':
description: Annotation deleted.
'401':
$ref: '#/components/responses/Unauthorized'
'403':
$ref: '#/components/responses/ProRequired'
'404':
$ref: '#/components/responses/NotFound'
'429':
$ref: '#/components/responses/RateLimited'
components:
responses:
NotFound:
description: Resource not found.
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
error:
code: not_found
message: The requested resource was not found.
RateLimited:
description: Rate limit exceeded.
headers:
Retry-After:
description: Seconds to wait before retrying.
schema:
type: integer
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
error:
code: rate_limited
message: Rate limit exceeded. Retry after 12 seconds.
ProRequired:
description: Active Matter Pro subscription required.
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
error:
code: pro_required
message: A Matter Pro subscription is required to use the API.
Unauthorized:
description: Invalid or missing API token.
content:
application/json:
schema:
$ref: '#/components/schemas/Error'
example:
error:
code: authentication_required
message: A valid API token is required.
parameters:
limit:
name: limit
in: query
description: Number of results per page. Min 1, max 100.
schema:
type: integer
default: 25
minimum: 1
maximum: 100
cursor:
name: cursor
in: query
description: Opaque cursor for the next page of results, from a previous `next_cursor`.
schema:
type: string
headers:
X-RateLimit-Reset:
description: Unix timestamp (seconds) when the window resets.
schema:
type: integer
X-RateLimit-Limit:
description: Maximum requests allowed in the current window.
schema:
type: integer
X-RateLimit-Remaining:
description: Requests remaining in the current window.
schema:
type: integer
schemas:
Error:
type: object
required:
- error
properties:
error:
type: object
required:
- code
- message
properties:
code:
type: string
description: Machine-readable error code.
message:
type: string
description: Human-readable error message.
field:
type: string
description: The request field that caused the error, if applicable.
PaginatedList:
type: object
required:
- object
- results
- has_more
properties:
object:
type: string
const: list
results:
type: array
items: {}
has_more:
type: boolean
description: Whether there are more results after this page.
next_cursor:
type: string
nullable: true
description: Cursor to fetch the next page. `null` when there are no more results.
Annotation:
type: object
required:
- object
- id
- item_id
- text
- created_at
- updated_at
properties:
object:
type: string
const: annotation
id:
type: string
description: Prefixed annotation ID (e.g. `ann_m2k8v`).
example: ann_m2k8v
item_id:
type: string
description: The parent item ID.
example: itm_r9f3a
text:
type: string
description: The highlighted text.
example: The way to figure out what to work on is by working.
note:
type: string
nullable: true
description: User-added note, if any.
example: Core thesis of the essay
created_at:
type: string
format: date-time
example: '2026-03-30T18:32:00Z'
updated_at:
type: string
format: date-time
example: '2026-03-30T18:32:00Z'
securitySchemes:
bearerAuth:
type: http
scheme: bearer
description: 'Personal API token with `mat_` prefix. Generate one at https://web.getmatter.com/settings.
'