> ## Documentation Index > Fetch the complete documentation index at: https://docs.engini.ai/llms.txt > Use this file to discover all available pages before exploring further. # Subscribe to trigger events > A text/event-stream response carrying the same event shape GET /v1/triggers/{triggerId}/events returns, one per data: {json} line, for events dispatched from the moment of connection onward. Near-real-time rather than a true push: events are picked up on a roughly one-second interval. Filters combine with AND: triggerId (must be yours - a foreign or unknown id is a 404 before the stream opens), triggerSlug (an unrecognised slug simply matches nothing) and applicationSlug. since=te_... replays every event after that one and then continues live; omit it to start from now. A heartbeat comment is sent every 20 seconds on an otherwise idle stream - if two intervals pass with nothing at all, treat the connection as dead and reconnect with since set to the last event id you received. A connection is not open-ended: expect to reconnect. Always resume with since rather than assuming one stream will run forever, and be ready for an intermediary to close a long-lived connection earlier than the server would. Capped at 10 concurrent streams per account - one more than that gets a 429 with Retry-After. An opaque eng_ API key is re-checked periodically while the stream is open, so a key revoked mid-stream ends it. Every controlled end - a revoked key, an unreplayable since cursor, or the server shutting down - is signalled by a named terminal event rather than a dropped socket, so a client can tell a deliberate end from a network blip. ## OpenAPI ````yaml /api-reference/openapi.json get /v1/triggers/subscribe openapi: 3.0.0 info: title: Engini DeveloperAPI version: v1 description: 'Merged public developer API spec: Identity + WorkflowApi.' servers: - url: https://api.engini.io security: - Bearer: [] - ApiKey: [] tags: - name: Auth description: Identify the caller a Developer API request is authenticated as. - name: Applications description: >- Discover the applications (toolkits) available in Engini and their connection requirements. - name: Tools description: Browse and execute the tools exposed by Engini applications. - name: Toolsets description: Manage toolsets - named groupings of connections and tools. - name: McpServers description: >- Inspect and maintain MCP servers - the account-wide endpoints that expose Engini tools and workflows over the Model Context Protocol. Distinct from the MCPClient connection kind, which is Engini consuming a third-party MCP server. - name: Connections description: >- Manage connections to applications, including OAuth sign-in and default-connection selection. - name: Triggers description: >- Create triggers that fire when something changes in a connected app, and manage the destinations their events are delivered to. paths: /v1/triggers/subscribe: get: tags: - Triggers summary: Subscribe to trigger events description: |- A text/event-stream response carrying the same event shape GET /v1/triggers/{triggerId}/events returns, one per data: {json} line, for events dispatched from the moment of connection onward. Near-real-time rather than a true push: events are picked up on a roughly one-second interval. Filters combine with AND: triggerId (must be yours - a foreign or unknown id is a 404 before the stream opens), triggerSlug (an unrecognised slug simply matches nothing) and applicationSlug. since=te_... replays every event after that one and then continues live; omit it to start from now. A heartbeat comment is sent every 20 seconds on an otherwise idle stream - if two intervals pass with nothing at all, treat the connection as dead and reconnect with since set to the last event id you received. A connection is not open-ended: expect to reconnect. Always resume with since rather than assuming one stream will run forever, and be ready for an intermediary to close a long-lived connection earlier than the server would. Capped at 10 concurrent streams per account - one more than that gets a 429 with Retry-After. An opaque eng_ API key is re-checked periodically while the stream is open, so a key revoked mid-stream ends it. Every controlled end - a revoked key, an unreplayable since cursor, or the server shutting down - is signalled by a named terminal event rather than a dropped socket, so a client can tell a deliberate end from a network blip. operationId: Triggers_SubscribeTriggerEvents parameters: - name: triggerId in: query description: >- Optional ti_ filter. A foreign or unknown id 404s before the stream opens. schema: type: string nullable: true x-position: 1 - name: triggerSlug in: query description: Optional trigger-type slug filter. schema: type: string nullable: true x-position: 2 - name: applicationSlug in: query description: Optional filter to one application's triggers. schema: type: string nullable: true x-position: 3 - name: since in: query description: >- Optional te_ catch-up cursor - replay everything after this event, then continue live. schema: type: string nullable: true x-position: 4 responses: '200': description: >- A live text/event-stream of the caller's trigger events. Never actually documented with a body schema - SSE is not a single JSON document. '400': description: Bad request - malformed body or invalid parameters. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '401': description: Unauthorized - missing or invalid bearer token. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '403': description: Forbidden - the caller lacks access to the resource. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '404': description: >- The triggerId filter names a trigger instance that does not exist or is not this account's. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '410': description: >- The since cursor is unknown or has been pruned by retention (SINCE_PRUNED) - the gap cannot be replayed. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '429': description: >- The account already holds the maximum concurrent trigger streams. Retry-After names how long to wait. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Internal server error - an unexpected error occurred. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: - Bearer: [] - ApiKey: [] components: schemas: ErrorResponse: type: object description: >- Unified error envelope for every non-200 response from /api/DeveloperAPI/v1/*. See applications-tools-spec.md ยง"Error envelope". additionalProperties: false required: - errorCode - message - requestId - timestamp - path properties: errorCode: type: string description: Machine-readable error code identifying the failure. message: type: string description: Human-readable error message. requestId: type: string description: Identifier of the request, for support/correlation. timestamp: type: string description: Timestamp when the error occurred (ISO 8601). path: type: string description: Request path that produced the error. details: type: array description: Per-field validation details, when applicable. nullable: true items: $ref: '#/components/schemas/ErrorDetail' ErrorDetail: type: object description: A single field-level error detail within an ErrorResponse. additionalProperties: false required: - field - issue properties: field: type: string description: Name of the field the issue relates to. issue: type: string description: Description of the issue with the field. securitySchemes: Bearer: type: http description: Enter your JWT token scheme: bearer bearerFormat: JWT ApiKey: type: apiKey description: >- Opaque Developer API key (prefix `eng_`). Authenticates as the key's owner and resolves the account automatically. name: x-api-key in: header ````