Transport and client boundary

The public LooprigTransport interface covers the cold session surface: listSessions, readStatus, and readHistory, plus createSession, restoreSession, submit, respondGate, and interrupt. Each method parses its response through the SDK validators before resolving. Live SSE is a separate seam, which keeps request/response behavior independent from the long-lived event stream.

import {
  createBFFClient,
  createClient,
  type LooprigTransport,
} from "@looprig/client";

const browserClient: LooprigTransport = createBFFClient();
const appClient = createClient(browserClient);

const page = await appClient.listSessions({ skip: 0, limit: 25 });
const status = await appClient.readStatus("session-id");

createClient accepts any LooprigTransport, including a test double or a custom implementation. createBFFClient constructs the same-origin BFFTransport, whose default base path is /api/v1.

Choose a transport

BFFTransport is the normal browser choice. It calls relative /api/v1/... paths, carries a lazily minted CSRF token on control requests, and does not hold a bearer token. The BFF supplies the server-side credential when it forwards the request.

ServeTransport is for a trusted server-side caller, a Node process, a CLI, or a test harness that talks directly to pkg/serve. Its required baseUrl points at unprefixed /v1 routes. When token is supplied, shared HTTP plumbing sends Authorization: Bearer <token> on every request. A custom fetch can attach another authentication scheme.

import { ServeTransport } from "@looprig/client";

const serverClient = new ServeTransport({
  baseUrl: "https://serve.internal.example/v1",
  token: process.env.LOOPRIG_TOKEN,
});

const created = await serverClient.createSession({
  blocks: [{ type: "text", text: "Hello" }],
});

Both transports share one implementation of URL construction, JSON decoding, runtime validation, typed HTTP errors, and abort handling. This makes the same LooprigTransport contract usable by a browser adapter and a trusted service without duplicating protocol logic.

Source

The public client composition and its createBFFClient default are implemented in sdk/core/src/client.ts. The transport interface, shared HTTP implementation, BFFTransport, and ServeTransport are in sdk/core/src/transport.ts.

Proof

The transport implementation shows that both concrete classes satisfy LooprigTransport and share the response-validation path. The client module shows that createClient is a thin composition and that createBFFClient is the ergonomic same-origin entry point. Continue with SessionClient for a framework-neutral live facade or Events and live streams for the raw event plane.