> For the complete documentation index, see [llms.txt](https://docs.zeta.markets/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.zeta.markets/zeta-protocol/exchange-architecture/trading-mechanism.md).

# Trading Mechanism

Trading functions using an underlying central limit order book for each market / underlying asset. 

#### Placing Orders

On an insert order instruction, the public key for the underlying market for that particular product, as well as the price, size and side of the order must be passed in.

For more details about specific order types see [Order Types](/zeta-protocol/learn-how-to-trade-on-zeta/order-types.md).

**Tick sizes**

Orders can only be placed with a minimum tick size on insert. For orders which are below the minimum increment value, they will be rejected.

Minimum price fluctuation for all contracts - [see trading mechanism](/zeta-protocol/trading-specifications.md)

**Tick sizes**

Minimum trade lot size for all contracts - [see trading mechanism](/zeta-protocol/trading-specifications.md)