Two-way API integration means that there is an API (connector programming code) that allows information to be sent back and forth between two pieces of software. For example: if your shopping cart had a two-way API integration with QuickBooks, both pieces of software could tell each other when a sale has been made and inventory amounts for a particular item have changed. This is particularly useful to the inventory manager so they don’t have to manually update the database at the end of every day. Two-way API integration could also be used between your shopping cart and SalesForce so that when a new customer registers for your member portal, their contact information ports into SalesForce with a tag for what kind of customer they are automatically. This makes it easier for your VP of Sales to track sales conversions and where they came from, rather than having a sales engineer manually update and load that information on a daily basis.