generated: '2026-07-19'
method: derived
source: openapi/kurrent-kurrentdb-http-api-openapi.yml
searched: https://docs.kurrent.io/getting-started/concepts.html
notes: >-
  KurrentDB's data model is deliberately small. There is no rich object graph of business
  resources; there is an append-only log of events, streams that group them, and a handful of
  server-side constructs that read from or manage those streams. The relationships below are
  derived from the OpenAPI schema $refs and the path structure, and named against the concepts
  documented at https://docs.kurrent.io/getting-started/concepts.html.
entities:
- name: Event
  schema: '#/components/schemas/Event'
  description: >-
    A factual occurrence from the past — the atomic unit of storage. Immutable once written.
  identifier: eventId (client-generated UUID, also the idempotency key)
  fields:
  - eventId
  - eventType
  - data
  - metadata
  key_properties:
  - immutable
  - append-only
  - typed by name, not by schema inference
- name: Stream
  description: >-
    An ordered, named sequence of events, normally one per aggregate or entity instance. Streams
    are created implicitly by the first append. System streams are prefixed with $.
  identifier: stream name (path parameter)
  operations:
  - readStream
  - appendToStream
  - deleteStream
  - readAllStream
- name: StreamMetadata
  schema: '#/components/schemas/StreamMetadata'
  description: >-
    Retention, caching and access configuration attached to a stream — $maxCount, $maxAge,
    $cacheControl, $tb and $acl.
  operations:
  - readStreamMetadata
  - updateStreamMetadata
- name: StreamAcl
  schema: '#/components/schemas/StreamAcl'
  description: Read, write, delete and metadata permissions granted to users or groups on a stream.
- name: AtomFeed
  schema: '#/components/schemas/AtomFeed'
  description: A paginated read projection of a stream, returned as an AtomPub feed.
- name: AtomEntry
  schema: '#/components/schemas/AtomEntry'
  description: A single event as rendered inside an Atom feed, carrying its position and payload.
- name: PersistentSubscription
  schema: '#/components/schemas/PersistentSubscriptionSettings'
  description: >-
    A server-managed competing-consumer subscription group bound to a stream, with checkpointing,
    retry limits, message timeouts and a consumer strategy.
  identifier: (stream, subscription) pair
- name: Projection
  description: >-
    A JavaScript query that reads events from one or more streams and maintains derived state, a
    result, or emits events to new streams. Transient, one-time or continuous.
  identifier: projection name
  operations:
  - createContinuousProjection
  - getProjectionState
  - getProjectionResult
- name: ProjectionConfig
  schema: '#/components/schemas/ProjectionConfig'
  description: Runtime configuration of a projection — emit behaviour, checkpointing thresholds, batch sizes.
- name: User
  schema: '#/components/schemas/NewUser'
  description: A database user account, optionally a member of groups, used for HTTP Basic authentication.
  identifier: login
- name: Node
  description: A KurrentDB server instance; a cluster is a set of nodes with one elected leader.
relationships:
- from: Stream
  to: Event
  type: has_many
  via: ordered append position (event number)
- from: Event
  to: Stream
  type: belongs_to
  via: streamId
- from: Stream
  to: StreamMetadata
  type: has_one
  via: /streams/{stream}/metadata
- from: StreamMetadata
  to: StreamAcl
  type: has_one
  via: $acl
- from: Stream
  to: AtomFeed
  type: has_many
  via: paginated read (event number + count + direction)
- from: AtomFeed
  to: AtomEntry
  type: has_many
  via: entries
- from: AtomEntry
  to: Event
  type: has_one
  via: eventId
- from: Stream
  to: PersistentSubscription
  type: has_many
  via: /subscriptions/{stream}/{subscription}
- from: PersistentSubscription
  to: PersistentSubscriptionSettings
  type: has_one
  via: settings body
- from: Projection
  to: Stream
  type: has_many
  via: streams read by the projection query
- from: Projection
  to: Stream
  type: has_many
  via: emitted streams (when emit is enabled)
- from: Projection
  to: ProjectionConfig
  type: has_one
  via: /projection/{name}/config
- from: User
  to: StreamAcl
  type: has_many
  via: membership in $r/$w/$d/$mr/$mw entries
- from: Node
  to: Stream
  type: has_many
  via: the node's log
system_streams:
- name: $all
  description: The global stream of every event in the database, in commit order.
- name: $streams
  description: >-
    Index of stream names, maintained by the standard projections. Used by the Kurrent MCP server
    to enumerate available streams.
- name: $settings
  description: Holds the default ACL applied where a stream has none of its own.
identifier_conventions:
  event_id: Client-generated UUID; doubles as the idempotency key for appends.
  stream_name: >-
    Free-form string, conventionally category-dash-identifier (for example order-1234), which the
    standard by-category projection splits on.
  reserved_prefix: >-
    Names beginning with $ are reserved for system streams, system events and system projections.