Introduction

This document describes Cboe Titanium U.S. Options Binary Order Entry (BOE), the Cboe proprietary order entry protocol. Please note that the Cboe Titanium U.S. Options BOE protocol will be sunset on 11/02/26.

Where applicable, the terminology (e.g., time in force) used in this document is similar to that used by the FIX protocol to allow those familiar with FIX to more easily understand BOE. This document assumes the reader has basic knowledge of the FIX protocol.

BOE fulfills the following requirements:

• CPU and memory efficiency. Message encoding, decoding, and parsing are simpler to code and can be optimized to use less CPU and memory at runtime.
• Application level simplicity. State transitions are simple and unambiguous. They are easy to apply to a Member's representation of an order.
• Session level simplicity. The session level protocol (login, sequencing, replay of missed messages, logout) is simple to understand.

While Cboe strives to preserve feature parity between FIX and BOE where possible, some features may only be available in one protocol or the other.

All binary values are in little Endian (used by Intel x86 processors), and not network byte order.

Each message is identified by a unique message type. Not all message types are used in all Cboe's trading environments globally. A listing of the supported message types is provided in Quote Reason Codes.

All communication is via standard TCP/IP.