What is OpenBook?

What is OpenBook?
TabTrader Team
TabTrader Team
Reading time is 10 min
Publication date is

OpenBook has taken up the mantle of the once highly successful decentralized exchange Serum, which was forced to close its doors after the FTX collapse. Keep reading to learn more about OpenBook, how it works, and what sets it apart from other decentralized exchanges.

What is OpenBook?

OpenBook is a decentralized exchange platform built on the Solana blockchain with the goal to blend the advantages of centralized exchanges with the trustless and transparent nature of DeFi. It was created as a community-driven fork of Serum, the Solana-based decentralized exchange that had become defunct after the infamous collapse of its former backers, Alameda Research and FTX.

Serum was the first high-performance decentralized exchange to successfully implement the Central Limit Order Book (CLOB) execution model. This trade execution model is known for providing an optimal trading experience for users, however, it is usually difficult to implement on-chain due to its high scalability and throughput requirements. 

The Story of OpenBook: How FTX's Failure Birthed a Solana DEX

In November 2022, the crypto world was rocked by the collapse of FTX, one of the world's largest cryptocurrency exchanges at the time. Millions of traders were left unable to access their funds, and the resulting market volatility led to huge losses for many.

However, things got even worse when soon after the collapse, it was discovered that FTX had experienced a security breach and that the hackers had stolen millions of dollars worth of cryptocurrency from the exchange. This not only caused further damage to FTX's reputation but also raised a major concern among users of Serum, as it was revealed that the update keys for Serum were not in control of the SRM DAO but instead were connected by a private key to FTX. 

Thus, the breach meant that someone who got their hands on FTX's private key could potentially use it to negatively update the Serum program and harm its users. As a result, protocols such as Jupiter Exchange, Raydium Protocol, and Mango Markets elected to move away from Serum and issued warnings against its use.

But the importance of Serum for the Solana ecosystem was too great for the protocol to simply disappear. Therefore, to preserve the project, the Solana community came together and launched OpenBook, a community-driven fork of the Serum V3 project. This fork maintains all the original code from Serum while removing the ties with FTX and allowing the community to have shared custody of the protocol.

Comparing Trade Execution Models: Orderbook vs AMM

As mentioned above, OpenBook (as Serum's successor) follows a Central Limit Orderbook (CLOB) model, which is a trade execution model based on a transparent system that matches customer orders on a “price-time priority” basis. Buyers and sellers place bids and asks at specific prices and sizes, and trades execute when the bids and asks match. All orders are stored in an open record known as an orderbook.

Compared to the AMM (Automated Market Maker) model, which works by pooling liquidity from buyers and sellers and then dynamically adjusting prices based on the amount of buy and sell orders, the Central Limit Orderbook model offers increased transparency and provides users with more control over their trades.

Serum was the first decentralized exchange to successfully implement a fully on-chain orderbook, a feat made possible by Solana's high throughput and low execution costs.

How Does OpenBook work?

OpenBook operates by coordinating interactions between Solana accounts. A Solana account is a sequence of fixed-length bytes stored in a blockchain, each with a unique address. Some Solana accounts used by OpenBook are user-specific (OpenOrders accounts), while others are global and exist to control various functions on the platform.


Here is a list of some of the essential global Solana accounts involved in the operation of the platform:

  • Request Queue — holds all unprocessed order placement and cancellation requests.
  • Orderbook — stores information about all open orders.
  • Event Queue — reports the outputs from order matching.

 An OpenOrders account is a middleman account that stores all the information regarding a user's open orders on the OpenBook platform.

A Life Cycle of a Trade on OpenBook

OpenBook facilitates the trading process by executing the following steps:


Placing orders

Users fund their OpenOrders account from their SPL token account (wallet) and add an order to the Request Queue.

Matching Orders

The request is taken from the Request Queue and processed, then placed in the Orderbook. Any trades resulting from this process are reported in the Event Queue.

Consuming Events

Events are taken from the Event Queue and processed, resulting in updates to the OpenOrders account balances.


Users can transfer their funds from their OpenOrders account back to their SPL token account (wallet) at any time.

Why Is OpenBook Unique?


  • Decentralized orderbook. OpenBook is one of the few fully on-chain decentralized orderbook exchanges currently in existence. It offers a unique blend of convenience and security, combining the user experience of a centralized exchange with the safety and transparency of a DEX.
  • High-performance trading. OpenBook is built on Solana, a high-performance blockchain that, due to its unique design, is able to offer low transaction fees and fast execution times for decentralized applications. This makes trading on OpenBook secure, fast, and affordable.
  • Community governance. OpenBook is governed by its community of users. There are no centralized entities controlling the exchange, and all decisions are made through a democratic voting process.

Competitive Forces

Solana's Serum (now OpenBook) was the pioneering force behind on-chain orderbooks. However, with the advancement of other high-performance blockchains, it is now facing increased competition.


dYdX is currently a hybrid decentralized exchange that combines an orderbook and a matching engine, running on a centralized server, with a core exchange protocol built on Ethereum smart contracts and STARK (zero knowledge) rollups.

However, the next version of dYdX is set to be released as a standalone blockchain, built on the Cosmos SDK and Tendermint Proof-of-Stake consensus protocol. This version will feature a fully decentralized, off-chain orderbook, in which each dYdX Chain validator will run an in-memory orderbook and match the orders.

Near-based orderbooks

The Near Protocol is quickly becoming the go-to blockchain for orderbook-based decentralized exchanges with the growing popularity of orderbook DEXs such as Tonic, Spin, and Orderly.

NEAR is a proof-of-stake, layer-one blockchain that achieves fast and cheap transactions through the use of sharding, a technique that divides the blockchain into several smaller sub-chains. 

Aptos-based orderbooks

Aptos is a POS blockchain that boasts a theoretical transaction throughput of more than 150,000 transactions per second, enabled by its use of parallel execution. This makes it an attractive platform for orderbook-based DEXs, with several projects announcing the launch of Aptos-powered orderbooks, such as Econia and Ferum​​.


Sei positions itself as the first sector-specific layer-1 chain optimized for trading. It has a native orderbook, built using Cosmos SDKs, and aims to achieve a finality of 600 ms with market-based parallelization. Sei has already attracted a vibrant ecosystem of 100+ dApps building for use cases like spot trading, perpetual trading, prediction markets, and more.

OpenBook Performance: The Numbers

Despite being a very young project, OpenBook is already displaying impressive traction. On average, it records a daily trading volume of around $5 million and 8 million transactions. The total value locked currently as of late March 2023 is approximately $3 million.

The exchange currently lists 3727 trading pairs, with the most active pairs by trading volume being SOL/USDC, mSOL/USDC, and ETH/USDC.


The launch of Serum marked a turning point not just for the Solana ecosystem and the entire DeFi. It made the convenience of centralized exchanges available in the DeFi space and achieved unprecedented speed for order placement and funds management. OpenBook takes this legacy and builds upon it, creating an even more robust version of the exchange.​​


To try trading on OpenBook, you can use their web-based GUI or access the exchange through a third-party interface such as TabTrader. In addition to 30+ centralized exchanges, TabTrader now supports trading on DEXs, with OpenBook being the first.

Looking to get started in crypto trading?

Try TabTrader on mobile or web!