PayPal has purchased StackMob, a San Francisco-based mobile application development firm, for undisclosed amount.

Founded in 2010, StackMob offers a custom API (application programming interface) that makes it easier for developers to connect mobile applications to backend platforms such as Salesforce and SAP.

StackMob allows developers to integrate datastore application programming interfaces to scale mobile apps, push notification cloud services, analytics and support for enterprise systems.

The company has been backed by Trinity Ventures, Harrison Metal, Baseline Ventures, Founder Collective and Charles River Ventures.

PayPal CTO James Barrese said: "StackMob is best known for its outstanding work in developing a platform that lets developers and companies easily create and manage mobile applications.

"We are thrilled to have the StackMob team put those same skills and expertise toward enhancing PayPal’s technology stack."