learn-eventmodelers-api

name	learn-eventmodelers-api
description	Teaches an agent everything about the eventmodelers platform API — all endpoints, their purpose, request payloads, response shapes, authentication, and element types.

Eventmodelers Platform API Reference

You now have complete knowledge of the eventmodelers platform API. Use this reference whenever you need to call, implement, or reason about any endpoint.

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Architecture Overview

• Framework: Express.js + @event-driven-io/emmett (event sourcing)
• Adapter: @event-driven-io/emmett-expressjs
• Database: PostgreSQL via Knex
• Storage / Auth: Supabase
• Route discovery: Dynamic glob (**/routes{,-*}.js) loaded from dist/src/slices
• Base URL (local): http://localhost:3000

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Authentication & Headers

Header	Required	Purpose
Authorization	Some routes	Supabase JWT bearer token
x-user-id	Node operations	User identifier
x-causation-id	Optional	Event causation tracing
x-correlation-id	Optional	Correlation tracing

• CORS allowed origins: localhost:3000, localhost:3001, https://app.eventmodelers.ai

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Element Types

MODEL_CONTEXT  // Context/domain modeling container
CHAPTER        // Timeline/sequence container
ACTOR          // System participant (swimlane label)
AUTOMATION     // Automated action
API            // External service
SCREEN         // UI screen
COMMAND        // State-changing operation
EVENT          // Domain event
SPEC_ERROR     // Error scenario
TABLE          // Data table
READMODEL      // Query result / materialized view
SCENARIO       // GWT scenario
LANE           // Timeline row
SLICE_BORDER   // Slice boundary marker

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Standard HTTP Status Codes

Code	Meaning
200	OK with data
201	Created
204	No content
400	Validation error / bad input
401	Authentication required
404	Resource not found
409	Conflict (e.g. duplicate)
500	Server error

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1. Boards

File: src/slices/change/api-boards/routes.ts

POST /api/org/:orgId/boards/:boardId/events

Persist board/timeline row events as an array of mixed event types.

Request body: Array of node, comment, edge, or board events
Response: 200 — processed results array

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GET /api/boards

List all boards.

Response: 200 — Board[]

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DELETE /api/org/:orgId/boards/:boardId

Delete a board.

Response: 204

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GET /api/org/:orgId/boards/:boardId/events/search

Search events by node name.

Query params: name (string)
Response: 200 — matching event array

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GET /api/org/:orgId/boards/:boardId/events

Get all board events in sequence.

Response: 200 — event array

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GET /api/org/:orgId/boards/:boardId/nodes/:nodeId/comments

Get all comments for a node.

Response: 200 — comment array

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POST /api/org/:orgId/boards/:boardId/bucket

Create a Supabase storage bucket for the board.

Response: 200 — { ok: boolean, bucket: string, alreadyExisted: boolean }

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2. Chapters & Timelines

File: src/slices/change/api-chapters/routes.ts

POST /api/org/:orgId/boards/:boardId/chapters

Create a chapter node.

Request body: { position?: { x: number, y: number } }
Response: 200 — chapter data

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POST /api/org/:orgId/boards/:boardId/timelines/:timelineId/columns

Add a column to a timeline.

Request body: { index?: number } (integer index, optional)
Response: 200 — { columnId: string, index: number, totalColumns: number }

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DELETE /api/org/:orgId/boards/:boardId/timelines/:timelineId/columns/:columnId

Delete a column from a timeline. Removes the column and all its cells. Cannot delete the last column.

Response:

• 200 — { columnId: string, totalColumns: number }
• 400 — validation error (e.g. last column)
• 404 — timeline or column not found

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POST /api/org/:orgId/boards/:boardId/timelines/:timelineId/lanes

Add a lane (row) to a timeline.

Request body:

{
  type: 'actor' | 'interaction' | 'swimlane' | 'spec' | 'feedback'
  label?: string
  index?: number
  height?: number
}

Response: 200 — lane data

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POST /api/org/:orgId/boards/:boardId/timelines/:timelineId/cells/:cellId/drop

Drop a node into a timeline cell. Validates placement rules.

Request body: { nodeId: string, nodeType: ElementType }

Placement rules:

• swimlane lane → accepts EVENT
• interaction lane → accepts COMMAND, READMODEL
• actor lane → accepts SCREEN, AUTOMATION
• feedback lane → accepts markdown
• spec lane → accepts SPEC_NODE

Response:

• 200 — drop result
• 400 — placement violation
• 404 — cell or node not found

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3. Nodes

File: src/slices/change/api-nodes/routes.ts

All node endpoints require header: x-user-id

POST /api/org/:orgId/boards/:boardId/nodes/events

Submit node change events.

Request body: NodeChangeEvent[]

interface NodeChangeEvent {
  id: string                    // uuid
  eventType: 'node:created' | 'node:changed' | 'node:deleted'
  nodeId: string
  boardId: string
  timestamp: number             // unix ms
  userId?: string
  hash?: string                 // content hash
  changedAttributes?: string[]  // dot-paths e.g. 'meta.title'
  node?: {
    id: string
    data: {
      backgroundColor?: string
      title?: string
      type?: string
      url?: string
      // ...other node data fields
    }
  }
  meta?: {
    type: ElementType
    title?: string
    description?: string
    fields?: Record<string, unknown>
    // ...
  }
  edges?: Array<{
    id: string
    source: string
    target: string
    sourceHandle?: string
    targetHandle?: string
  }>
  chapterId?: string   // for cell placement
  cellName?: string    // spreadsheet-style e.g. "B2"
}

Response: 200 — { hashes: { [eventId: string]: string } }

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GET /api/org/:orgId/boards/:boardId/nodes

List all nodes on a board.

Query params: type?: ElementType
Response: 200 — node record array

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GET /api/org/:orgId/boards/:boardId/nodes/:nodeId

Get a single node.

Response: 200 — node record OR 404

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4. Images

File: src/slices/change/api-images/routes.ts

POST /api/org/:orgId/boards/:boardId/images/:imageId

Update a board image.

Request: multipart/form-data — field file (binary)
Response: 204

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POST /api/org/:orgId/boards/:boardId/imagesnapshots/:imageId

Update an image snapshot.

Request: multipart/form-data — field file (binary)
Response: 204

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POST /api/org/:orgId/boards/:boardId/image-nodes/:nodeId

Create an image node.

Request: multipart/form-data — fields: file, chapterId, cellName
Response: 204

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POST /api/org/:orgId/boards/:boardId/images/:imageId/sketch

Render a sketch description to WebP and upload.

Request body:

{
  elements: object[]           // sketch element descriptors
  semanticDescription?: string // human-readable description stored in metadata
}

Response: 204

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POST /api/org/:orgId/boards/:boardId/image-nodes/:nodeId/sketch

Create a SCREEN node from a sketch description.

Request body:

{
  chapterId: string
  cellName: string
  description: { elements: object[] }
  semanticDescription?: string
}

Response: 204 OR 400 (validation error)

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5. Slices

File: src/slices/change/api-.slices/routes.ts

POST /api/org/:orgId/boards/:boardId/timelines/:timelineId/slices

Create a complete slice (1 column + 3 nodes automatically placed).

Request body:

{
  type: 'state-change' | 'state-view' | 'automation'
  index?: number
  nodes?: {
    actor?: Partial<NodeData>
    interaction?: Partial<NodeData>
    swimlane?: Partial<NodeData>
  }
}

Slice node mapping:

• state-change → SCREEN (actor) + COMMAND (interaction) + EVENT (swimlane)
• state-view → SCREEN (actor) + READMODEL (interaction) + EVENT (swimlane)
• automation → AUTOMATION (actor) + COMMAND (interaction) + EVENT (swimlane)

Response: 200 — slice data

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6. Specifications (GWT Scenarios)

File: src/slices/change/api-specs/routes.ts

POST /api/org/:orgId/boards/:boardId/contexts/:contextName/slices/:sliceName/scenarios

Append a Given-When-Then scenario to a spec node.

Request body:

{
  id: string
  title: string
  vertical?: boolean
  examples?: unknown[]
  given: string[]   // nodeIds — must be EVENTs from same timeline
  when: string[]    // nodeIds — at most one COMMAND; empty if then has READMODEL
  then: string[]    // nodeIds — EVENTs only OR exactly one READMODEL (not mixed)
}

Validation rules:

• given: only EVENTs from same timeline
• when: max one COMMAND; must be empty when then contains a READMODEL
• then: all EVENTs OR exactly one READMODEL — never mixed
• All referenced nodes must belong to the same chapter/timeline

Response:

• 201 — { scenario, scenarios, specNodeId, isNewNode: boolean }
• 400 — validation error
• 404 — context or slice not found
• 409 — duplicate scenario title

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GET /api/org/:orgId/boards/:boardId/contexts/:contextName/spec-info

Get valid elements for a context (by name lookup).

Response: 200 — { chapterId: string, elements: ElementRecord[] }

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GET /api/org/:orgId/boards/:boardId/contexts/:contextName/slices/:sliceName/spec-info

Get valid elements for a specific slice.

Response: 200 — { chapterId: string, elements: ElementRecord[] }

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7. Config Import

File: src/slices/change/config-import/routes.ts

POST /api/org/:orgId/boards/:boardId/import-config

Import an EventModelingJson config to populate a board.

Request: multipart/form-data with field file OR application/json body:

{ slices: SliceDefinition[] }

Response: 200 — transformed canvas with nodes and edges

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8. Slice Data

File: src/slices/slicedata/routes.ts

GET

Build structured slice data from board state.

Query params (one required): contextId OR contextName; optional: sliceId
Response: 200 — slice data matching event modeling schema

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GET /api/org/:orgId/boards/:boardId/slicedata/slices

List all slices on a board.

Response: 200 — { slices: Array<{ id: string, title: string, status: string }> }

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9. Extensions

File: src/slices/extensions/routes.ts

GET /api/org/:orgId/boards/:boardId/extensions

List extension configs for a board.

Response: 200 — extension record array

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PUT /api/org/:orgId/boards/:boardId/extensions/:type

Enable or disable an extension.

Request body: { enabled: boolean, config?: object }
Response: 200 — updated extension config

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10. Snapshots

File: src/slices/Snapshots/routes.ts

All snapshot endpoints require Supabase JWT authentication.

Constraints: max 3 snapshots per user, max 30-day retention, max 50 MB file size.

GET /api/snapshots

List current user's snapshots.

Response: 200 — Array<{ id, name, payload_id, expiry, shared }>

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POST /api/snapshots

Create a snapshot.

Request: multipart/form-data — fields: payloadFile (binary), name (string), retention? (days, max 30)
Response: 201 — { ok: true, id: string }

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GET /api/snapshots/:id

Load a snapshot's payload.

Response: 200 — snapshot payload JSON

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PATCH /api/snapshots/:id/share

Share a snapshot (makes it publicly accessible).

Response: 200 — { ok: true }

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DELETE /api/snapshots/:id

Delete a snapshot.

Response: 200 — { ok: true }

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11. User Management — Commands (Event Sourced)

All commands respond with:

{
  ok: true
  next_expected_stream_version: number
  last_event_global_position: number
}

Optional headers on all: correlation_id, causation_id

POST /api/creategroup

Body: { groupId: string, name: string }
Event emitted: GroupCreated

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POST /api/inviteuser

Body: { groupId: string, email: string, invitationId: string }
Event emitted: UserInvited

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POST /api/acceptinvite

Body: { userId: string, groupId: string, invitationId: string }
Event emitted: InvitationAccepted

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POST /api/assignrole

Body: { userId: string, groupId: string, role: string }
Event emitted: RoleAssigned

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12. User Management — Read Models (Projections)

All require authentication. Optional query param _id to filter by ID.

GET /api/query/group-details-lookup

Group details. Filter: ?_id=groupId

GET /api/query/open-invites

Pending invitations. Filter: ?_id=invitationId

GET /api/query/user-group-assignments

User-to-group mappings. Filter: ?_id=groupId

GET /api/query/users-to-assign-to-groups

Users available for group assignment. Filter: ?_id=userId

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13. Utility

GET /api/user

Get current authenticated user info.

Response: { user_id: string, email: string, metadata: object }

GET /api-docs

Swagger UI (interactive API explorer)

GET /swagger.json

OpenAPI specification (JSON)

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Domain Events

Snapshot Events (src/events/SnapshotsEvents.ts)

SnapshotStored          // { name, id, payloadId, expiry }
SnapshotDeleted         // { id }
SnapshotCleanedUp       // { id }
PublishedSnapshotDeleted // { id }
SnapshotShared          // { id }
SnapshotPublished       // { id, payloadId, bucket, path }

User Management Events (src/events/UserManagementEvents.ts)

GroupCreated          // { groupId, owner, name }
UserAssignedToGroup   // { groupId, userId }
UserInvited           // { groupId, invitationId, email }
InvitationAccepted    // { invitationId, groupId, userId }
RoleAssigned          // { groupId, userId, role }

All events support optional metadata: user_id, correlation_id, causation_id

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Key Source Files

File	Purpose
src/slices/change/types.ts	ElementType, NodeChangeEvent, EdgeEvent
src/slices/change/api-boards/routes.ts	Board CRUD + event persistence
src/slices/change/api-chapters/routes.ts	Chapters, columns, lanes, cell drops
src/slices/change/api-nodes/routes.ts	Node event sourcing
src/slices/change/api-images/routes.ts	Image upload + sketch rendering
src/slices/change/api-.slices/routes.ts	Slice creation
src/slices/change/api-specs/routes.ts	GWT scenario management
src/slices/change/config-import/routes.ts	Config import
src/slices/slicedata/routes.ts	Slice data read models
src/slices/extensions/routes.ts	Extension management
src/slices/Snapshots/routes.ts	Snapshot CRUD
src/slices/usermanagement/*/routes*.ts	User management commands + projections
src/events/SnapshotsEvents.ts	Snapshot domain events
src/events/UserManagementEvents.ts	User management domain events
backend/src/server.ts	Route wiring, CORS, /api/user