Auth0 offers identity as a service, but it's not what you think.

IDaaS typically refers to a hosted service, like one from Centrify, that handles authentication and authorization. An IT department signs up for such a service to handle authentication for users who need to sign into apps.

Auth0 offers that, but it's more focused on offering a service designed to make it easier for developers to build authentication and authorization into their apps.

"We created Auth0 to take what's traditionally been an especially complex environment, a process that can be weeks or months, down to hours or days," said John Gelsey, CEO of Auth0.

Developers can use Auth0 to let end users log in via 40 different social identity providers, like Facebook and LinkedIn, as well as enterprise ID providers, like Active Directory. Developers essentially drop code into their apps and then Auth0 handles the authentication. Auth0 customers pay based on the number of end users who authenticate each month.

The company this morning is announcing a $2.4 million investment led by Bessemer Venture Partners.

Auth0 says its service is used by 8,000 developers and IT managers around the world. Big name customers include Schneider Electric, MindJet, Allegion, and Berkshire Hathaway Travel Protection.

It got into those businesses by focusing on the developers there, Gelsey said. "The common theme is the developers at those enterprises discovered us and adopted us for enterprise wide use," he said.

Auth0 has set up an unusual backend. The service runs on both Amazon Web Services and Azure. While it's not that unusual for a service to use different public clouds, typically a service will use one as a backup or run a discrete portion of an app on one cloud. In Auth0's case, the service can be running entirely in either cloud. "It's symmetrical so from moment to moment it could be Azure or AWS," he said. The setup is designed to offer serious reliability.

While the size of Auth0's user base is impressive, the company faces some stiff competition. While providers like Okta might be best known for their single sign on service, some also offer services that let developers easily drop in authentication. Salesforce's Identity service can also be used by developers to add authentication to their apps. Businesses that are already using single sign on service from a provider like Okta or Salesforce might find it easiest to stick with it for identity as a service in their own apps.

Gelsey said the company will use the new investment to expand its product development and marketing efforts. However, he said he's particularly interested in the advice he hopes to get from some of the new funders.