ProgrammableWeb lists more than 16,000 application program interfaces in its directory, up from just 300 decade ago, and the market is expanding by about 40 new entrants per week. But building applications that use multiple APIs can require some gymnastics.

That’s why RapidAPI is trying to help with an open source platform that enables developers worldwide to find and connect them. The blue-chip venture capital firm Andreessen Horowitz LLC today said is helping it along its journey with an investment of $3.5 million.

RapidAPI was founded last year by Israeli entrepreneur Iddo Gino when he was just 17 years old.  The company is tackling a problem that is common to fast-growing new industries: chaos. Ever since eBay Inc. and Salesforce.com Inc. kicked off the API revolution in 2000 by exposing selected services for others to use, developers have been piling in, but with little coordination and few standards.

APIs provide a way for organizations to expose services and data for others to use while maintaining control of the software. For example, a simple program can combine APIs from Fitbit Inc.’s fitness tracker and a cell phone carrier’s text messaging service to automatically send an alert if a person has failed to meet the day’s fitness goals by a specified time.

The problems arise when many APIs are connected in a sophisticated enterprise application. “A [customer relationship management platform] can predict a company’s sales volume, but the [enterprise resource planning platform] ERP cannot automatically use it to order raw materials,”  Gino wrote in a Medium post announcing the funding. “For a developer connecting to hundreds of APIs, it can be an impossible mess to navigate.”

Numerous API integration services have emerged, ranging from simple stitching platforms like IFTTT to enterprise-oriented commercial services like Elastic.io GMBH. RapidAPI is open source, and Gino said it intends to stay that way.

The company provides a directory of published APIs, along with details on the features of each one and instructions on how to use them. Registered members can use the company’s open source tools to connect APIs together with a small code snippet. The company says it already has more than 25,000 developers in its community and is working with enterprise customers, including eBay Inc.

Founder Gino “painted a very clear vision for the company as the go-to place for accessing APIs, differentiated by speed, reliability, and simplicity,” wrote Martin Casado, an Andreessen Horowitz general partner and one of the principal developers of software-defined networking. “His vision is backed by a passionate and voracious community that has steadily grown in small amount of time.”

Google thought API management was important enough to spend $625 million to buy Apigee Inc. two months ago. RapidAPI and its investor are clearly hoping lightning will strike twice.