Part of the massive success of Fortnite has been the ability for hundreds of millions of players to join with each other across myriad computer, mobile, and console platforms. Now, Epic is laying out a roadmap to share that cross-platform architecture with other developers as part of a free SDK that will be rolled out next year.

Epic says its newly announced Online Services SDK will offer "cross-platform login, friends, presence, profile, and entitlements" across PC, Mac, iOS, Android, PlayStation, Xbox, and Switch "to the full extent each platform allows per-title." The service is planned for launch on PC sometime in the second or third quarter of 2019, with support for other platforms planned "throughout 2019."

A roadmap announced today laid out the following schedule for features to be added to the free SDK:

Q2 2019: Cross-platform data storage and cloud-saved games

Q3 2019: Cross-platform achievements and trophies; voice communications; PC/Mac overlay

Q3/Q4 2019: Cross-platform parties and matchmaking

Further support for "user-generated content, enhanced social features, anti-cheat, and more" are also planned after the above "first steps" are completed, Epic said.

The C-based SDK will launch with Unreal Engine and Unity integration, but it will also be completely open to all engines and freely mergeable with other online solutions, Epic said. The online infrastructure will be built primarily on top of Amazon Web Services, as is the case with Fortnite, and may support Google's Cloud Platform in the future. Epic also promises full compliance with Europe's GDPR.

"Successfully launching and operating a live, online game requires a suite of services that go far beyond the functionality of a traditional game engine," Epic said in a statement. "These services are expensive to build, test, and harden in real-world conditions, but once operational, are relatively inexpensive to scale to more games and more users. At Epic, our goal is to help game developers succeed."

"Epic has put huge efforts into building services for Fortnite that reach 200 million players across seven platforms," Epic Founder and CEO Tim Sweeney said in a statement. "Now we’re working to open up these services to all developers on all platforms, all stores, and all engines for free.”

Epic's online service roadmap announcement comes just a week after the company announced its Epic Games Store , a major effort that offers developers a better revenue share than Valve's market-leading Steam platform. The store launched last week with quite a bit of fanfare but an extremely limited selection of games

The announcement also comes at a time when full cross-platform support for online gameplay and features is changing from the exception to the norm in the game industry. Sony, which for years had steadfastly refused to let its PlayStation Network integrate with other console services, recently opened up after pressure from major publishers including Epic and Bethesda.