How to Live Trade on Composer

In this article, you'll learn how to paper trade a symphony on Composer with our Alpaca API integration.

Connecting to Alpaca

The first step is to connect your Composer account with your Alpaca account. If you don’t have an Alpaca account, you can set one up for paper trading from anywhere in the world.

In Composer, head over to the menu with your name on it and select “connect to Alpaca”.

Next, authorize Composer to access your account information and to place transactions in your Alpaca account. By agreeing, you grant Composer permission to place paper and live transactions in your Alpaca account, following the symphonies in your Composer account that you assign to Paper Trading and Live Trading, respectively. 

Wait for the authentication, and you’re ready to go.

Setting a symphony to live trading

For now, you can assign a maximum of one symphony to live trade in your brokerage account in Alpaca. To do that, open up the symphony in the Editor and change the status of the symphony from Testing to Live Trading. Please ensure your Alpaca Live Trading account has been funded with a minimum of $2000 prior to setting your symphony to a Live Trading status.

Note: Symphonies can only be set to Live Trading and executed while the market is open (typically 9:30 am to 4 pm EST on weekdays).

The assets making up your symphony will be bought and sold according to the specifications of the symphony at the trading frequency you specified (i.e., daily, weekly, etc.). 

If you have a symphony set to Live Trading and then set a different symphony to Live Trading, the symphony previously set to Live Trading will be moved to Testing (i.e., that symphony will only exist in your Composer account).

Fractional trades

Composer's backtesting tool assumes that fractional trading would have been used throughout the backtest period to match the intended symphony allocations. 

Live symphony execution will use fractional trading if it is available in the brokerage for the assets held in the symphony. If fractional trading is not supported in the brokerage or if fractional trading is not supported for some symphony assets, Composer will buy or sell the number of shares needed rounded down to the nearest whole number. A list of assets for which Alpaca supports fractional trading can be found here.

Turning off a live trading symphony

To turn off a live trading symphony, set the symphony's status to Testing. The symphony's positions will be closed in your connected brokerage account. 

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