QuickBooks Online is software for managing your business finances and accounting. HubSpot is software for managing your customer relationships and sales. Sometimes, you might want information from your QuickBooks accounting to be shared with your HubSpot customer system, or vice versa. To make this possible, there is a special computer program (an app) that can connect QuickBooks and HubSpot together. This app acts as a bridge, allowing data to flow between the two systems. You can find this connecting app in the HubSpot Marketplace, which is HubSpot's own store for add-ons. The app covers most of the common data you'd want to share between accounting and customer systems. However, the pre-built ready-to-use integration app cannot cover absolutely everything that your business needs. This is where custom QuickBooks and HubSpot integration enters the scene.