With the rise of on-demand enterprise software from Salesforce.com (CRM) to Zuora (online billing), businesses using more than one service still have to figure out how to send data from one system to the other, and hook into their old legacy data-center software as well. A startup called Boomi is aiming to solve that problem. It raised its first $4 million institutional round of venture financing today from FirstMark Capital.

Boomi is targeting small and medium-sized businesses that don’t have the IT resources to do this integration work on their own. It can connect Software-as-a-Service (SaaS) applications to each other and to data center apps.

Some examples of SaaS-to-SaaS integrations it can handle are Salesforce, NetSuite, Intacct, SmartTurn, Zuora, and Taleo. It can also integrate those with on-premise applications such as QuickBooks, Microsoft Great Plains, and SAP (or directly into a database using an FTP or HTTP connection). Here is a list of all the applications it supports.