The Jolla phone - pronounced Yol-la - is powered by open-source operating system Sailfish, but can run most apps designed for Google's Android platform.
The company has paired with a major Finnish network, and hopes to set up a similar deal with a UK operator.
Industry analysts said Jolla faced a challenge in taking on a market dominated by Google and Apple.
Just 450 Jolla phones will be available at launch on Wednesday evening, with the majority going to customers who have pre-ordered the device.
Co-founder Marc Dillon told the BBC the company was in the process of ramping up manufacturing.
He said the phone's ethos was to provide a more "open" approach to how people used their mobiles, a contrast to the relatively closed systems used on the iPhone and, to a lesser extent, Android devices.
"There's different opportunities for people to get apps form different places, different stores," he said.
"We've created a world-class platform. Users will be getting more choice."
Dumped OS
The platform - originally called MeeGo - was developed by Nokia, but dumped in 2011 in favour of the company adopting the Windows Phone system.
Source : BBC News
No comments