> For the complete documentation index, see [llms.txt](https://docs.alt.town/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.alt.town/alt.town-service/town-trading/orderbook.md).

# On-chain Based Trading

Once the pre-sale period ends, you can continue trading on the order-book. Order-book trading is executed through the matching of buy and sell orders, allowing users to sell the DNA they have purchased or buy new quantities.

The order methods provided by Alt.town are as follows:

## **Limit Order**

* A limit order is a type of order submitted by a user who manually enters the price and quantity of DNA they wish to buy or sell.
* This order type is used when price is a priority, ensuring that the order will not be executed at a price higher than the specified buy price or lower than the specified sell price.
* If a sell order is place at a price lower than the current market price or a buy order is placed at a price higher than the current market price, it will be executed at the market price.
* Even if the specified price is reached, limit orders may not be executed due to the order method execution mechanism (price > time priority).

{% hint style="danger" %}
Depending on trade execution conditions, the pending order may not be fully executed.
{% endhint %}

## **Market Order**

* A market order is an order submitted without specifying a price.
* This order method is used when you want to execute a trade quickly. By setting only the order amount for a buy order or the order quantity for a sell order, the trade will be executed immediately at the market price.
  * Buy Order: If users set only the order amount, it will be immediately executed at the lowest price among the current ask prices.
  * Sell Order: If users set only the order quantity, it will be immediately executed at the highest price among the current bid prices.
* When a market order is placed, it will be executed sequentially, starting from the most favorable price (best bid/ask).

{% hint style="danger" %}
Orders may be rejected for the protection of users’ assets. Please refer to the order rejection criteria if your market order is rejected.
{% endhint %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.alt.town/alt.town-service/town-trading/orderbook.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.