> ## Documentation Index
> Fetch the complete documentation index at: https://docs.parlayx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Stream live orderbooks and trades with the @parlayx/sdk/stream client

`@parlayx/sdk/stream` is a typed WebSocket client for the ParlayX orderbook
stream. It wraps the raw [WebSocket API](/streaming/overview) — the handshake,
subscription bookkeeping, keepalive, and reconnect-with-resubscribe — behind a
small `createStreamClient` surface, and delivers every server frame as a typed
event.

It ships inside `@parlayx/sdk` as the `@parlayx/sdk/stream` subpath, so there's
nothing extra to install — see [Installation](/sdk/installation).

## When to use it

Reach for the streaming client when you need **live** market data: a full
orderbook snapshot followed by a continuous, gap-free stream of price-level
changes, and optionally the market's public trade tape.

For everything else — placing and managing orders, reading balances, one-off
market lookups — use the REST client from [`@parlayx/sdk`](/sdk/quickstart). The
two are complementary: stream prices in, route orders out.

## What you get

* **Typed frames.** `on("snapshot", handler)` hands you a fully typed
  `SnapshotFrame`; each event's handler is narrowed to that frame's shape.
* **Automatic resubscribe.** Subscriptions are replayed on every reconnect, so a
  dropped connection is transparent to your application.
* **Keepalive & reconnect.** Ping/pong liveness and exponential-backoff reconnect
  are built in.

Continue to [Authentication](/sdk/stream/authentication) to set up a stream key,
then the [Quickstart](/sdk/stream/quickstart).