---
title: FIX API
description: Read market data, place and manage limit orders, and negotiate request-for-quote trades through the UDX FIX APIs over FIX 5.0 SP2.
sidebar:
  label: Overview
---

The FIX APIs support market data, order book trading, and request-for-quote (RFQ) negotiation over FIX 5.0 SP2, using the FIXT 1.1 session protocol.

Browse the [Market Data](/api-reference/fix/market-data) and [Order Entry](/api-reference/fix/order-entry) references for message layouts, field values, and dictionary downloads.

Session messages manage the FIX session, beginning with [Logon](/api-reference/fix/session-messages/logon). Application messages carry market data and trading requests and reports. Both message levels use the shared [header and trailer](/api-reference/fix/header-and-trailer).

See [FIX Data Types](/reference/fix-data-types) for wire formats and examples, and [FIX Message Layouts](/reference/fix-message-layouts) for field ordering and presence rules.

See [FIX Sessions and Recovery](/reference/fix-sessions-and-recovery) for logon, reconnects, and order-entry replay.

## Market Data

Read the instrument catalog, follow trading statuses, and subscribe to order books and trades. See [Market Data](/concepts/market-data) for order book views and [Markets and Trading](/concepts/markets-and-trading) for pricing and units.

Start with [Discovering Markets](/walkthroughs/fix/discovering-markets), then follow [Reading Market Data](/walkthroughs/fix/reading-market-data).

## Order Entry

Place, amend, and cancel limit orders, and receive execution reports for their lifecycle and fills. See [Order Entry](/concepts/order-entry) for the trading concepts and [Markets and Trading](/concepts/markets-and-trading) for pricing and units.

Follow [Placing Orders](/walkthroughs/fix/placing-orders) for the order lifecycle and fee accounting.

Create an RFQ as a taker or answer one with a quote as a maker. FIX carries the negotiation through quote acceptance, last look, and execution. See [RFQs](/concepts/rfqs) for the lifecycle and the roles of takers and makers.

Follow [Requesting Quotes](/walkthroughs/fix/requesting-quotes) as a taker or [Providing Quotes](/walkthroughs/fix/providing-quotes) as a maker.

## FIX Access

Contact support for information about onboarding to FIX.