Paper Trading

When you run your algorithm with the live market, there are many things that can happen that you may not see in backtesting. Orders may not be filled, prices may spike, or your network may get disconnected and retry may be needed. During the software development process, it is important to test your algorithm to catch these things in advance.

Paper trading is a real-time simulation environment where you can test your code. Everything on the broker side behaves the same way as the live account except the orders aren’t routed to the real exchanges. Instead, the system simulates the order filling based on the real-time quotes. It calculates the account balance and performance numbers with virtual money so the real money in your live account isn’t affected by the activity in the paper trading account. You may create one paper trading account per live account.

Create A Paper Trading Account

Your initial paper trading account is created with $100k balance as a default setting. You can reset the paper trading account at any time later with arbitrary amount as you configure. After it is created, the account works independently from your live account. You have to have your brokerage account with any amount of funding to create a paper trading account.


You are creating a paper trading account with initial balance amount of $600. You place orders in the paper trading account using this $600, and let’s say the net worth increases to $650. In the meantime, if you didn’t trade anything in the live account, your live account net worth wouldn’t change. In other words, the paper trading account is initialized with the net worth of the live account, but they are independent of one another thereafter.

How to Start Using Paper Trading Account

Your paper trading account will have a different API key from your live account, and all you need to do to start using your paper trading account is to replace your API key and API endpoint with ones for the paper trading. The API spec is the same between the paper trading and live accounts. The API endpoint (base URL) is displayed in your paper trading dashboard, and please follow the instruction about how to set it depending on the library you are using. In most cases, you need to set an environment variable APCA_API_BASE_URL=

Reset Paper Trading Account

You can reset your paper trading account at any time from the dashboard. Go to the paper trading view and push the reset button. Once you reset the paper trading account, the trading history of the paper trading account is wiped out, and a new paper trading account is created based on your requested initial balance. Please make sure to re-generate the API key as old key is associated with your old paper trading account and is not valid any longer after you reset it.


  • Paper trading account simulates our pattern-day-trader checks. Orders that would make 4th day trading within 5 business days will be rejected if the real-time net worth is below $25,000. Please read the Pattern Day Trader Protection page for more details.
  • Paper trading account does NOT simulate dividends.
  • Paper trading account does NOT send order fill emails.
  • Market Data API works identically.
  • You cannot change the account balance after it is created, unless you reset it.
  • Orders are filled at the NBBO at the moment, although the size of order book is not considered.
  • Orders may be partially filled at a predefined random rate.