> For the complete documentation index, see [llms.txt](https://docs.candyswap.gg/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.candyswap.gg/information/order-book.md).

# Order Book

### What is an Order Book? 

An Orderbook is an trading protocol, used primarily in the stock exchange but has recently been an emerging presence in the crypto space. A *matching engine* uses this to determine which orders can be fully or partially executed. 

#### Buy and Sell 

The two main participants in an order book are the 'buyer' and the 'seller'. The buyer (the 'buy') bids for a certain amount of tokens at a specific price. This demand is then satisfied by the seller (the 'sell'), who asks for a particular fee for their tokens. A list of 'buys' and 'sell(s)' is generated with the matching engine pairing deals that satisfy both parties. 

#### Visual Representation

An *order book depth chart* dynamically shows the list of bids and asks for a specific commodity. A general rule of practice is that the buys are shown on the left and the sells on the right. 

<figure><img src="/files/xcfj7NSW2y5ttNeSqc3e" alt=""><figcaption><p>Figure 1 - An Order book depth chart shows the buys in green, and the sells on the right are in red. The x-axis is the unit price; the y-axis is cumulative order depth (<a href="https://en.wikipedia.org/wiki/Order_book#/media/File:Order_book_depth_chart.gif">https://en.wikipedia.org/wiki/Order_book#/media/File:Order_book_depth_chart.gif</a>)</p></figcaption></figure>

#### Order Book Terminology&#x20;

**Price Point**&#x20;

When multiple orders are the same price, they are referred to as a *price point*, meaning that if a bid comes at that *price level*, the sell orders could potentially fulfil it.   &#x20;

**Top of the book**

The top of the book is the highest buy and the lowest sell.&#x20;

**Book depth**

The book depth is the number of price levels available at a particular time.&#x20;