sandbox-agent/docs/manage-sessions.mdx

---
title: "Manage Sessions"
description: "Persist and replay agent transcripts across connections."
icon: "database"
---

Sandbox Agent stores sessions in memory only. When the server restarts or the sandbox is destroyed, all session data is lost. It's your responsibility to persist events to your own database.

See the [Building a Chat UI](/building-chat-ui) guide for understanding session lifecycle events like `session.started` and `session.ended`.

## Recommended approach

1. Store events to your database as they arrive
2. On reconnect, get the last event's `sequence` and pass it as `offset`
3. The API returns events where `sequence > offset`

This prevents duplicate writes and lets you recover from disconnects.

## Receiving Events

Two ways to receive events: SSE streaming (recommended) or polling.

### Streaming

Use SSE for real-time events with automatic reconnection support.

```typescript
import { SandboxAgentClient } from "sandbox-agent";

const client = new SandboxAgentClient({
  baseUrl: "http://127.0.0.1:2468",
  agent: "mock",
});

// Get offset from last stored event (0 returns all events)
const lastEvent = await db.getLastEvent("my-session");
const offset = lastEvent?.sequence ?? 0;

// Stream from where you left off
for await (const event of client.streamEvents("my-session", { offset })) {
  await db.insertEvent("my-session", event);
}
```

### Polling

If you can't use SSE streaming, poll the events endpoint:

```typescript
const lastEvent = await db.getLastEvent("my-session");
let offset = lastEvent?.sequence ?? 0;

while (true) {
  const { events } = await client.getEvents("my-session", {
    offset,
    limit: 100
  });

  for (const event of events) {
    await db.insertEvent("my-session", event);
    offset = event.sequence;
  }

  await sleep(1000);
}
```

## Database options

Choose where to persist events based on your requirements. For most use cases, we recommend Rivet Actors.

| | Durable | Real-time | Multiplayer | Scaling | Throughput | Complexity |
|---------|:-------:|:---------:|:-----------:|---------|------------|------------|
| Rivet Actors | ✓ | ✓ | ✓ | Auto-sharded, one actor per session | Millions of concurrent sessions | Zero infrastructure |
| PostgreSQL | ✓ |  |  | Manual sharding | Connection pool limited | Connection pools, migrations |
| Redis |  | ✓ |  | Redis Cluster | High, in-memory | Memory management, Sentinel for failover |

### Rivet Actors

For production workloads, [Rivet Actors](https://rivet.gg) provide a managed solution for:

- **Persistent state**: Events survive crashes and restarts
- **Real-time streaming**: Built-in WebSocket support for clients
- **Horizontal scaling**: Run thousands of concurrent sessions
- **Observability**: Built-in logging and metrics

#### Actor

```typescript
import { actor } from "rivetkit";
import { Daytona } from "@daytonaio/sdk";
import { SandboxAgent, SandboxAgentClient, AgentEvent } from "sandbox-agent";

interface CodingSessionState {
  sandboxId: string;
  baseUrl: string;
  sessionId: string;
  events: AgentEvent[];
}

interface CodingSessionVars {
  client: SandboxAgentClient;
}

const daytona = new Daytona();

const codingSession = actor({
  createState: async (): Promise<CodingSessionState> => {
    const sandbox = await daytona.create({
      snapshot: "sandbox-agent-ready",
      envVars: {
        ANTHROPIC_API_KEY: process.env.ANTHROPIC_API_KEY,
        OPENAI_API_KEY: process.env.OPENAI_API_KEY,
      },
      autoStopInterval: 0,
    });

    await sandbox.process.executeCommand(
      "nohup sandbox-agent server --no-token --host 0.0.0.0 --port 3000 &"
    );

    const baseUrl = (await sandbox.getSignedPreviewUrl(3000)).url;
    const sessionId = crypto.randomUUID();

    return {
      sandboxId: sandbox.id,
      baseUrl,
      sessionId,
      events: [],
    };
  },

  createVars: async (c): Promise<CodingSessionVars> => {
    const client = new SandboxAgentClient({
  baseUrl: c.state.baseUrl,
  agent: "mock",
});
    await client.createSession(c.state.sessionId, { agent: "claude" });
    return { client };
  },

  onDestroy: async (c) => {
    const sandbox = await daytona.get(c.state.sandboxId);
    await sandbox.delete();
  },

  run: async (c) => {
    for await (const event of c.vars.client.streamEvents(c.state.sessionId)) {
      c.state.events.push(event);
      c.broadcast("agentEvent", event);
    }
  },

  actions: {
    postMessage: async (c, message: string) => {
      await c.vars.client.postMessage(c.state.sessionId, message);
    },

    getTranscript: (c) => c.state.events,
  },
});
```

#### Client

<CodeGroup>

```typescript TypeScript
import { createClient } from "rivetkit/client";

const client = createClient();
const session = client.codingSession.getOrCreate(["my-session"]);

const conn = session.connect();
conn.on("agentEvent", (event) => {
  console.log(event.type, event.data);
});

await conn.postMessage("Create a new React component for user profiles");

const transcript = await conn.getTranscript();
```

```typescript React
import { createRivetKit } from "@rivetkit/react";

const { useActor } = createRivetKit();

function CodingSession() {
  const [messages, setMessages] = useState<AgentEvent[]>([]);
  const session = useActor({ name: "codingSession", key: ["my-session"] });

  session.useEvent("agentEvent", (event) => {
    setMessages((prev) => [...prev, event]);
  });

  const sendPrompt = async (prompt: string) => {
    await session.connection?.postMessage(prompt);
  };

  return (
    <div>
      {messages.map((msg, i) => (
        <div key={i}>{JSON.stringify(msg)}</div>
      ))}
      <button onClick={() => sendPrompt("Build a login page")}>
        Send Prompt
      </button>
    </div>
  );
}
```

</CodeGroup>

### PostgreSQL

```sql
CREATE TABLE agent_events (
  event_id TEXT PRIMARY KEY,
  session_id TEXT NOT NULL,
  native_session_id TEXT,
  sequence INTEGER NOT NULL,
  time TIMESTAMPTZ NOT NULL,
  type TEXT NOT NULL,
  source TEXT NOT NULL,
  synthetic BOOLEAN NOT NULL DEFAULT FALSE,
  data JSONB NOT NULL,
  UNIQUE(session_id, sequence)
);

CREATE INDEX idx_events_session ON agent_events(session_id, sequence);
```

### Redis

```typescript
// Append event to list
await redis.rpush(`session:${sessionId}`, JSON.stringify(event));

// Get events from offset
const events = await redis.lrange(`session:${sessionId}`, offset, -1);
```

## Handling disconnects

The SSE stream may disconnect due to network issues. Handle reconnection gracefully:

```typescript
async function streamWithRetry(sessionId: string) {
  while (true) {
    try {
      const lastEvent = await db.getLastEvent(sessionId);
      const offset = lastEvent?.sequence ?? 0;

      for await (const event of client.streamEvents(sessionId, { offset })) {
        await db.insertEvent(sessionId, event);
      }
    } catch (error) {
      console.error("Stream disconnected, reconnecting...", error);
      await sleep(1000);
    }
  }
}
```