What is the pricing model for using ALPACA service

I am new here, I wanted to inquire for what is the cost of using ALPACA services, plus can I use to build a trading application where other buyers can buy and sell using my platform?

Advance Thank you from a newbie

Alpaca doesn’t charge anything for setting up an account and using the APIs. There are also no commissions charged for trades. However, there are typically small SEC and FINRA fees added for stock sales. These are mandatory fees and passed through to the customer. There are also margin interest and short borrowing fees if one uses margin or sells a stock ‘short’.

Alpaca encourages developers to create applications to enable user to live trade. Developers are free to set whatever prices they wish for their applications. Alpaca does not charge any fees or take a percentage of that. Note this is for live trading. Paper trading only applications have some restrictions on the number of users.

Be aware there are two general approaches for 3rd parties to trade The simplest is for an application to use OAuth to effectively trade on behalf of an account holder. Setting up an account, funding it, and withdrawing cash are all still done via the Alpaca site. The other approach is for a 3rd party to actually hold the accounts, receive funds, etc. The Alpaca relationship from the users perspective is transparent. This is less simple and currently requires the 3rd party to be a registered broker/dealer.