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

# Overview

> Event-driven connectivity for payments and trading.

## WebSocket API Options

Paxos offers two WebSocket API solutions for different use cases:

### Public WebSocket API

Open access to real-time market and execution data feeds via public [WebSocket](https://websocket.spec.whatwg.org) connections. Ideal for DMA (Direct Market Access) to itBit and general market data consumption. No authentication required.

### Smart Order Routing WebSocket API

Authenticated, bidirectional WebSocket API exclusively for Smart Order Routing platform customers. Provides request-response operations and streaming data with OAuth2 authentication. [Learn more](/api-reference/websockets/smart-order-routing-overview).

> Smart Order Routing customers should use the authenticated [Smart Order Routing WebSocket API](/api-reference/websockets/smart-order-routing-overview) for enhanced functionality and authorized access.

## Public WebSocket API

The public WebSocket API offers three main data feeds:

* **[Execution Data Feed](#execution-data-feed)** - Real-time execution data for market trades
* **[Market Data Feed](#market-data-feed)** - Order book updates with initial snapshots and real-time updates
* **[Stablecoin Market Price Feed](#stablecoin-feed)** - Market index price updates for external stablecoins

> See the Websocket [trading](/guides/crypto-brokerage/websocket) guide for a hands-on introduction.

The WebSocket connections provide a number of advantages when compared to the [v2 API](/api-reference), including real-time event notifications, minimized data transfers over the network and reduced latency when compared to a polling strategy.

## API Reference

For detailed technical specifications, message schemas, and interactive examples, see the **API Reference** section in the sidebar. The AsyncAPI specification provides complete documentation for all available channels, message types, and data formats.

## Connection Details

Once a secure (`wss://`) connection is established, each feed begins streaming data, subject to the [rate limits](/guides/developer/rate-limits#websocket-limits).
Both Production and Sandbox data feeds have a built-in, instantaneous failover.
Clients should have a reconnection mechanism in case of server disconnection.

### Server Endpoints

**Production:** `wss://ws.paxos.com`\
**Sandbox:** `wss://ws.sandbox.paxos.com`

### Available Channels

* `/executiondata` - All markets execution data
* `/executiondata/{market}` - Single market execution data
* `/marketdata` - All markets order book data
* `/marketdata/{market}` - Single market order book data
* `/marketdata/stablecoin/{market}` - Stablecoin market price data

> See the **API Reference** section for detailed channel specifications and message formats.

## Execution Data Feed

The execution data feed provides real-time trade information for market executions. Key behavioral characteristics:

* **Initial Message**: The first message corresponds to the last execution at connection time
* **Subsequent Messages**: Each new message represents a new execution as it occurs
* **Idle Markets**: If no executions occur for extended periods, no messages are sent until new activity
* **Reconnection**: Upon reconnection, you receive the last execution (handle duplicates using `match_number`)

The feed includes execution price, amount, timestamp, and a unique match number for deduplication.

## Market Data Feed

The market data feed provides real-time order book updates with two message types:

### SNAPSHOT Messages

* **Initial Response**: Shows the complete order book state with bids and asks
* **Bids**: Prices in descending order with amounts
* **Asks**: Prices in ascending order with amounts

### UPDATE Messages

* **Real-time Updates**: Show executed trades and order book changes
* **Processing Rules**:
  * When `amount=0`: Remove the price level from the order book
  * When `amount>0`: Add or update the price level with the new amount
  * Use `side` field to determine whether to update bids (`BUY`) or asks (`SELL`)

### Available Markets

Market availability varies by environment (Sandbox vs Production) and account restrictions. Use the [Get Order Book](/api-reference/endpoints/market-data/get-order-book) and [List Recent Executions](/api-reference/endpoints/market-data/list-recent-executions) REST endpoints to discover available markets, though these are not suitable for streaming data.

## Stablecoin Market Price Feed

The stablecoin market price feed provides real-time market index price updates for external stablecoins. Key characteristics:

* **Current Support**: USDCUSD market
* **Update Frequency**: Typically \~1 message per second, varying with market volatility
* **Message Content**: Market name, current price (4 decimals), and timestamp
* **Real-time Updates**: Price updates are pushed as they occur

This feed is particularly useful for applications requiring accurate, real-time stablecoin pricing information.