Last updated 2026-05-07

SSE Events

The runner exposes a Server-Sent Events stream at GET /api/events. Every state change in every run is multicast to all subscribers — the CLI's stax log -f, the dashboard, and anything else you point at it.

Connection

curl -N http://localhost:4800/api/events

Headers:

Content-Type: text/event-stream
Cache-Control: no-cache
Connection: keep-alive

Event types

Event	Payload	Meaning
`ping`	`{}`	Sent on connect and every 30 s as keepalive.
`run.started`	`{ runId, run }`	Workflow execution started.
`run.completed`	`{ runId, run }`	Run finished (any conclusion).
`job.started`	`{ runId, jobId, job }`	Job execution started.
`job.completed`	`{ runId, jobId, job }`	Job finished.
`step.started`	`{ runId, jobId, stepNumber, step }`	Step execution started.
`step.completed`	`{ runId, jobId, stepNumber, step }`	Step finished.
`step.log`	`{ runId, jobId, stepNumber, line }`	One stdout/stderr line from a step.

Sample stream

event: ping
data: {}

event: run.started
data: {"runId":"a1b2c3d4","run":{"id":"a1b2c3d4","status":"in_progress","jobs":[]}}

event: job.started
data: {"runId":"a1b2c3d4","jobId":"build","job":{"name":"build","steps":[]}}

event: step.started
data: {"runId":"a1b2c3d4","jobId":"build","stepNumber":1,"step":{"name":"Checkout"}}

event: step.log
data: {"runId":"a1b2c3d4","jobId":"build","stepNumber":1,"line":"Workspace already available\n"}

event: step.completed
data: {"runId":"a1b2c3d4","jobId":"build","stepNumber":1,"step":{"conclusion":"success"}}

event: job.completed
data: {"runId":"a1b2c3d4","jobId":"build","job":{"conclusion":"success"}}

event: run.completed
data: {"runId":"a1b2c3d4","run":{"status":"completed","conclusion":"success"}}

Browser client

const events = new EventSource('http://localhost:4800/api/events');

events.addEventListener('run.started', (e) => {
  const { runId, run } = JSON.parse(e.data);
  console.log('Run started', runId);
});

events.addEventListener('step.log', (e) => {
  const { runId, jobId, stepNumber, line } = JSON.parse(e.data);
  appendToTerminal(runId, jobId, stepNumber, line);
});

events.addEventListener('run.completed', (e) => {
  const { run } = JSON.parse(e.data);
  console.log('Run', run.id, 'finished:', run.conclusion);
});

TypeScript types

type SSEEventType =
  | 'run.started'
  | 'run.completed'
  | 'job.started'
  | 'job.completed'
  | 'step.started'
  | 'step.completed'
  | 'step.log';

interface SSEEvent<T = unknown> {
  type: SSEEventType;
  runId: string;
  jobId?: string;
  stepNumber?: number;
  data: T;
}