openapi: 3.1.0
info:
  title: Spring Boot Admin Server Applications Events API
  description: REST API for the Spring Boot Admin server. Manages application registration, instance monitoring, Actuator endpoint proxying, and lifecycle event streaming. Spring Boot Admin is a community project by codecentric AG that provides a web UI for monitoring and managing Spring Boot applications via their Actuator endpoints.
  version: 3.3.0
  contact:
    name: codecentric AG
    url: https://github.com/codecentric/spring-boot-admin
  license:
    name: Apache 2.0
    url: https://www.apache.org/licenses/LICENSE-2.0
servers:
- url: http://localhost:8080
  description: Local Spring Boot Admin server
tags:
- name: Events
  description: Instance lifecycle event stream
paths:
  /instances/events:
    get:
      operationId: streamInstanceEvents
      summary: Stream Instance Events
      description: Server-Sent Events (SSE) stream of all instance lifecycle events. Events include REGISTERED, DEREGISTERED, STATUS_CHANGED, INFO_CHANGED, and ENDPOINTS_DETECTED.
      tags:
      - Events
      responses:
        '200':
          description: SSE event stream of instance lifecycle events
          content:
            text/event-stream:
              schema:
                $ref: '#/components/schemas/InstanceEvent'
components:
  schemas:
    InstanceEvent:
      type: object
      description: A lifecycle event for an application instance (delivered via SSE)
      properties:
        instance:
          type: string
          description: Instance ID this event is about
          example: abc123def456
        version:
          type: integer
          description: Event version number (monotonically increasing)
        timestamp:
          type: string
          format: date-time
          description: When this event occurred
        type:
          type: string
          description: Event type
          enum:
          - REGISTERED
          - DEREGISTERED
          - STATUS_CHANGED
          - INFO_CHANGED
          - ENDPOINTS_DETECTED
        statusInfo:
          $ref: '#/components/schemas/StatusInfo'
        info:
          type: object
          description: Updated info payload (for INFO_CHANGED events)
          additionalProperties: true
    StatusInfo:
      type: object
      description: Status information for an application instance
      properties:
        status:
          type: string
          description: Current instance status
          enum:
          - UP
          - DOWN
          - OUT_OF_SERVICE
          - UNKNOWN
          - RESTRICTED
          - OFFLINE
        details:
          type: object
          description: Additional status details from the health endpoint
          additionalProperties: true