Zuora was admitted to Azure's chi-chi hand-picked TAP club as its charter cloud-based billing supplier when the two-year-old start-up, with some handholding by Microsoft, delivered the Zuora Toolkit for Windows Azure, which developers and ISVs can use to monetize their pay-as-you-go Azure cloudware.

They'll be able to meter, price and bill for the apps and services.

The widgetry, like all in the Technology Adoption Program (TAP), is supposed to help drive the success and adoption of the Azure ecosystem and abet the shift away from perpetual licenses and one-time fees.

Zuora's Toolkit is supposed to let developers create flexible price plans and packages; support usage and pay-as-you-go pricing models; initiate a subscription order online; accept credit cards with PCI Level 1 compliance; and manage customers, recurring subscriptions and invoicing.

Zuora president Shawn Price says, "The single most important service for ISVs in the cloud is the ability to monetize, and Zuora removes the friction of building a payment ecosystem and manages the constant changes that come with subscription management." He advises against trying to build a billing system from scratch if you're in a different line of work. It's a bitch.

See http://developer.zuora.com/.

Zuora also has a Z-Commerce for the Cloud code sample for developers to embed in their cloud solutions at http://developer.zuora.com/samplecode.html.

Zuora folks are out of salesforce.com, WebEx, eBay and Vitra and the company got its $21.5 million in funding from Benchmark Capital, Shasta Ventures, salesforce CEO Marc Benioff and PayPal president Scott Thompson. It handles nine million cloud transactions a day at EMC. Other cloud customers include Tata, Zetta and cloud providers in Holland, Australia and Mexico.