# Platform Concepts

- [Rate Limits](/docs/learn/platform-concepts/rate-limits.md)
- [Backtesting](/docs/learn/platform-concepts/backtesting.md): Backtesting is a critical tool for any trader that is running automated trading strategies. It uses historical data to determine the effectiveness of a strategy in different market conditions.
- [Order Behavior](/docs/learn/platform-concepts/order-behavior.md): This page documents the behavior of TradersPost when receiving different types of strategy signals.
- [Order Queueing](/docs/learn/platform-concepts/order-queueing.md): Order queueing is used when an order cannot be sent to the broker when the market is closed and TradersPost will queue these orders to be sent at the next market open.
- [Order Classes](/docs/learn/platform-concepts/order-classes.md): This page provides an overview of the different order classes available in TradersPost and it explains the functionalities and use cases of these orders.
- [Paper Trading](/docs/learn/platform-concepts/paper-trading.md): Paper trading is a useful tool for being able to forward test your automated trading strategies without having to risk real money.
- [Position Sizing](/docs/learn/platform-concepts/position-sizing.md): TradersPost offers several different features for dynamically and manually managing your position size.
- [Fractional Shares](/docs/learn/platform-concepts/fractional-shares.md): TradersPost supports trading in fractional share quantities with brokers that support it. The following brokers support fractional trading: