Bessemer Venture Partners have called up to back San Francisco cloud based communications provider Twilio, with a $12m Series B funding round. Also participating were Union Square Ventures, 500 Startups and several individual Angel investors.

The Twilio system allows net programmers to easily mash up pay-as-you-go telecoms, including text and other phone-based applications, into their websites.  Twilio’s SaaS platform does all the communications work, presenting developers with simple plug-in and standard APIs. Developers like it: over 20,000 customers are using Twilio – including Ebay, Media Temple, Salesforce, Sony and Survey Monkey.

Byron Deeter from Bessemer Venture Partners will now join the Twilio Board of Directors, as will Ty Wang, a former Director of Communications at Oracle, who will be the new VP of Business Development.

Twilio is also great for start-ups and other small websites, as it has a simple pay-as-you-go pricing model. Users only pay for the telephony or SMS texts they actually use and there are no start-up costs or onerous contracts.

Developers like Twilio because it has everything they need in just six simple API building blocks. This reduces the cost of developing, deploying and managing voice and SMS apps by freeing staff from detailed telecoms handling and allowing users to pay for capacity when it is needed – and not before.

SOURCE: WiredVC.com