Server-Sent Events

Stream CRDT deltas to stateless clients via SSE.

Meridian exposes a Server-Sent Events endpoint for clients that cannot maintain a persistent WebSocket — serverless functions, Lambda, Cloudflare Workers, or AI agents.

GET /v1/namespaces/:ns/crdts/:id/events
Authorization: Bearer <token>
Accept: text/event-stream

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Event format

Each event carries a single base64-encoded msgpack delta:

data: <base64-encoded msgpack delta>\n\n

The delta has the same structure as WebSocket deltas — decode the base64, then decode the msgpack payload as a CRDT delta.

Keep-alive pings are sent every 15 seconds to prevent proxy timeouts. Lagged receivers (those that fall too far behind the broadcast buffer) are silently skipped — reconnect to catch up.

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Example

const es = new EventSource(
  `https://your-server.com/v1/namespaces/my-app/crdts/counter/events`,
  { headers: { Authorization: `Bearer ${token}` } }
);

es.onmessage = (event) => {
  const bytes = Uint8Array.from(atob(event.data), c => c.charCodeAt(0));
  const delta = decode(bytes); // msgpack decode
  console.log("delta:", delta);
};

es.onerror = () => {
  // reconnect automatically — EventSource retries by default
};

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Auth

The token must have read permission for the CRDT ID. The namespace in the token must match the :ns path parameter.

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Comparison with WebSocket

	WebSocket	SSE
Direction	Bidirectional	Server → client only
Writes	Yes (ops over WS)	No — use POST /ops
Persistent connection	Yes	Yes (HTTP keep-alive)
Serverless compatible	No	Yes
Reconnect on drop	Manual	Automatic (browser EventSource)

Use SSE when your client only needs to react to changes. For reads and writes from serverless agents, combine SSE with POST /v1/namespaces/:ns/crdts/:id/ops. See AI Agents for a complete example.