Succeeding in software today means testing and tweaking new features with the speed and efficiency of Amazon, Facebook and Google.

But most companies don't have the resources and technical talent to keep up. That's the opportunity LaunchDarkly is attacking.

LaunchDarkly built what it calls a "feature management platform" that any business can use to test, manage and provision software features. Mimicking the tech giants, the start-up's platform lets companies make different features available to select groups without shipping everything to everyone at the same time.

That strategy has lured clients including GoPro and has excited investors. LaunchDarkly just raised $21 million from Redpoint Ventures and Vertex Ventures.

"We started off with developers loving us first," said Edith Harbaugh, LaunchDarkly's CEO and co-founder. "But our real customers end up being the rest of the business, like marketing experts and salespeople selling contracts. They can turn on this feature or that one for whoever's paying for it and leave developers to concentrate on awesome code."

In addition to GoPro, LaunchDarkly is used by a range of hardware makers, government agencies, banks, shipping companies and travel firms. (Harbaugh said she did not have permission to name her clients publicly.)

Harbaugh said that had Macy's been using LaunchDarkly, the retailer could have avoided their recent credit card payments outage over Black Friday. "Macy's could have just turned off its buggy code, and let their good code keep functioning," she said.

Harbaugh, an ultrarunner who has competed in more than 35 very long-distance races, started the company with John Kodumal, the chief technology officer in 2014. The start-up plans to use its new capital for hiring, educating prospective clients and connecting with developers.