---
seo:
  description: >-
    The versioned public WebSocket contract for live UDX market data. Clients
    authenticate and negotiate udx.json.2026-08-11 during the HTTP Upgrade,
    then…
sidebar:
  label: Overview
title: WebSocket API
---
The versioned public WebSocket contract for live UDX market data. Clients authenticate and negotiate `udx.json.2026-08-11` during the HTTP Upgrade, then exchange the JSON messages defined here. This version supports authenticated public L2 order books only; L1, L3, and private account channels are not part of this closed contract. Every concept and identifier on the wire belongs to the UDX public model.

<ApiOverview source="websocket-api" />

## Market Data

Live public order book subscriptions and recovery.

<ApiTagOperations source="websocket-api" tag="market-data" />