# Stream events over SSE

Source: https://langbot.ai/docs/api/websocket/stream-sse

`GET /v1/stream/sse`

The same stream as the WebSocket over Server-Sent Events, for networks that block WebSockets.

**Auth.** None. Without a token the call is served as Free (the Free delay and request budget, shared per IP); send `Authorization: Bearer lb_…` for your plan's.

**Limits.** Counts toward your plan's concurrent streams, WebSocket and SSE together (1, 5 or 20). Served at your plan's delay (+60 s Free, +10 s Builder, +2 s Standard).

## Parameters

### Query parameters

| Name | Type | Required | Description |
|---|---|---|---|
| `events` | string | no | Comma-separated event ids (`ev_…`). |
| `phrases` | string | no | Comma-separated phrase keys. |
| `types` | string | no | Comma-separated event types. |
| `subjects` | string | no | Comma-separated typed-fact subjects. |
| `context` | string | no | Context kinds to opt in to: `on_air`, `topic`, `near_miss`, `typed` or `all`. |

## Request

**curl**

```bash
curl -N -H "Authorization: Bearer $LANGBOT_API_TOKEN" \
  "https://api.langbot.ai/v1/stream/sse?phrases=tariff&types=phrase_detected"
```

**Python**

```python
from langbot import LangbotClient

async with LangbotClient() as lb:
    async for evt in lb.stream_sse(phrases=["tariff"], types=["phrase_detected"]):
        print(evt.event_id, evt.phrase, evt.t_spoken)
```

**TypeScript**

```ts
import { LangbotClient } from "@langbotai/sdk";

const lb = new LangbotClient();
for await (const evt of lb.streamSSE({ phrases: ["tariff"], types: ["phrase_detected"] })) {
  console.log(evt.event_id, evt.phrase);
}
```

## Response

`200 OK`

```text
event: hello
data: {"type":"hello","seq":9032,"delay_ms":60000,"plan":"anonymous","effective_plan":"free",…}

event: phrase_detected
data: {"id":"evt_01M6…","type":"phrase_detected","phrase":"tariff",…}
```

`text/event-stream`: the event type is the SSE `event:` and the JSON is `data:`; keep-alives are SSE comments (`: ping`).

## Errors

| Status | `code` | When |
|---|---|---|
| 401 | `token_invalid` | A token was sent and not recognised. Send a valid one, or none to call anonymously. |
| 422 | `validation_error` | A parameter failed validation; `detail[].loc` names it. |
| 429 | `rate_limited` | Over your request budget; wait `Retry-After` seconds. |

Every error body is `{"detail": …, "code": "…"}`; branch on `code`. All codes: [Errors](https://langbot.ai/docs/api#errors).