Open source software developer Mozilla has announced that its official Firefox devices are now on sale in stores in Spain. Telefonica is selling the low-cost handsets built on Open Web Technologies the handsets, in Madrid.

The ZTE Open is available through the operator’s Movistar stores for €69, including €30 of balance for prepaid customers and a 4GB microSD card. Poland, Colombia and Venezuela will see similar handset launches soon, according to Mozilla, and they will be arriving in further countries later.

Developers can upload and share their apps in the Firefox Marketplace, and the Firefox OS allows them to accept payments for apps and in-app purchases. Mozilla has also launched the Firefox OS Simulator, a tool to help developers test their apps quickly.

With the Firefox handsets aimed at the low end segment of the market, it had been rumoured that Telefonica would first launch the handsets in Brazil, according to Malik Saadi principal analyst at Informa Telecoms and Media. However, he said that with Spanish operators seriously cutting device subsidies and due to the economic downturn, launching in Spain is a wise move.

“The most popular handsets in Spain are in the low-end mid-range segments, rather than the iPhones or Galaxy S4s,” he said.

“My only concern is that the ecosystem has not been built yet, Mozilla is relying on web developers to develop this ecosystem, and its future depends on how attractive the device is to the end user.”

Many developers may question whether the platform will serve a wide audience, Saadi explained, whereas some are not incentivised by revenues but by the challenge of developing an app that looks native in a web environment.

Another issue could be how well the handsets are marketed, and Telefonica will have a huge role to play in this, said Saadi.

“Telefonica knows Spain better than anybody, and this could really help the case of Mozilla,” he said.

He added that the fact the handset is made by Chinese vendor ZTE is another bonus for Firefox, as it is a fairly well known manufacturer that specialises in low end handsets, and has optimised hardware to sit in that price point.

The Alcatel One Touch Fire is also expected to launch soon with support from European operator group Deutsche Telekom in Poland in the coming weeks.