R Software Inc., the company behind RapidAPI, which has built a developer-focused marketplace for application programming interfaces, said today it has raised $25 million in a round of funding led by Microsoft Corp.’s venture capital arm M12.

Andreessen Horowitz, Green Bay Capital, and DNS Capital also participated in the Series B round, which brings RapidAPI’s total funding to $37.5 million.

APIs are lightweight programming interfaces used by developers to integrate their software applications with other apps and services. They’re an essential building block for all kinds of apps. For example, any app that integrates Google LLC’s Maps service for example, uses an API to do so.

RapidAPI’s marketplace is hugely popular with developers because it provides them with access to thousands of publicly available APIs, covering everything from web search to sports results and breaking news. The company also provides a simple interface through which developers can manage all of their API connections in one place.

With its new funds, RapidAPI says it plans to scale its API marketplace and also push its newly released RapidAPI for Teams product. It’s a self-service platform that enables developers to publish, manage and collaborate on APIs and microservices, which are common components used to build modern apps. The company launched RapidAPI for Teams in preview last year for select enterprises, and today it’s making it available for smaller developer teams as well, priced at $10 per developer per month.

“Ten years ago, companies would develop software as a single monolith,” RapidAPI founder and Chief Executive Officer Iddo Gino said in a statement. “With the shift to microservices, that monolith is deconstructed to hundreds of external APIs and dozens of internal APIs. We started RapidAPI to help developers better manage and consume external APIs, and now we enable them to share and collaborate on internal APIs too, allowing them to work with greater velocity and efficiency.”

RapidAPI is gunning for a piece of the growing API management market that some analysts say will be worth $5.1 billion a year by 2023. It’s not alone in that endeavor, though, as it faces competition from major technology firms including Google, Microsoft and also Amazon Web Services Inc.

Google, for example, built its API management service after acquiring a company called Apigee Inc. for $625 million in 2016, while Microsoft did the same thing following its acquisition of Apiphany Inc. back in 2013.

Image: RapidAPI