PubNub raises $4.5M to bring real-time messaging to apps

San Francisco-based startup PubNub, which provides real-time messaging to web and mobile apps, just raised a $4.5 million Series A round of financing led by new fund Relay Ventures and Silicon Valley’s TiE Angels. The funding comes after PubNub broke a recent milestone of processing more than 100,000 messages per second.
PubNub launched in the summer of 2010 and now serves more than 1,000 customers, offering up a cloud-based service for distributing real-time messages at massive scale. The company is used by apps in social media, massively multiplayer mobile gaming, and even business collaboration  — basically anything that needs to synchronize communications between large groups of people all at once.
The company is kind of like Akamai (s AKAM) for messaging, with different distributed nodes in nine data centers around the world that relay messages between applications within a tenth of a second. With two transparent pricing plans, it charges clients based on the number of messages and the capacity that they need.
On the low end, there’s the PubNub Go service, which provides a self-serve option for smaller businesses. PubNub Go costs $15 a month, with customers paying an addition $10 for 10 million messages. For those customers who need more help, the startup offers PubNub Galaxy, which defines pricing based on the number of messages sent as well as the capacity of real-time connections.
PubNub can be used for mobile applications on a number of different platforms and development frameworks, including iOS, (s AAPL) Android, (s GOOG) JavaScript, (s ORCL) Blackberry, (s RIMM) Windows Phone, (s MSFT) Node.JS, Python, Ruby and more.
After two years of bootstrapping, the startup currently has 10 full-time employees and 10 contractors. According to CEO Todd Greene, who joined PubNub after the sale of his last startup, Loyalize, to Function(x) (maker of the Viggle second-screen social TV app), the funding will be used to expand the platform and add more features to the service.
As a side note, PubNub’s financing is one of the first public investments by Relay Ventures, a new fund devoted to enabling new mobile app technologies. Other investments by Relay include Appcelerator, Appia, QuickPlay Media and Xobni. Founding members of the Relay Ventures team include investors from JLA Ventures, RBC Venture Partners and Woodside Fund, among others.