Learn about Zero-K, a free open-source RTS game with physically simulated units, terrain manipulation, large multiplayer battles, and a PlanetWars campaign.
Zero-K is a free, open-source real-time strategy game, not business software. It began around 2007 as a community-made mod for the Spring engine, an open-source engine originally built for Total Annihilation-style games, and evolved into a fully independent title once its remaining copyrighted content was stripped out, with the standalone project taking shape around 2010.
The game is built and maintained entirely by a volunteer community rather than a commercial studio or publisher. It's distributed for free with no in-game currency or microtransactions, available directly from the Zero-K project as well as on Steam, where it launched on April 27, 2018.
Because Zero-K is a game rather than a SaaS or business tool, it has no company headquarters, employee count, or commercial pricing structure in the conventional sense; its listing here reflects its status as a well-known, free, open-source title.
Zero-K's combat is driven by physically simulated units and projectiles rather than purely scripted outcomes, and its terrain can be actively reshaped during matches, letting players dig canals, raise ramps, or build fortifications as part of their strategy.
The game includes more than 100 distinct unit types with unique abilities, along with customizable commander units that let players tailor their starting strategy. A single-player campaign features AI opponents designed to compete without cheating by accessing hidden information.
Multiplayer support ranges from 1v1 duels to large 16v16 battles, plus free-for-all and cooperative modes. PlanetWars, a persistent online competitive campaign, ties individual match outcomes into an ongoing meta-game across the player community.
Zero-K is completely free to download and play, with no purchase price, subscription, or in-game currency of any kind.
The project explicitly markets itself as having no pay-to-win mechanics or unfair monetization, funded and developed instead by its volunteer contributor community.
There are no premium tiers, DLC, or paid add-ons; the entire game, including all units, maps, and the PlanetWars campaign, is available to every player at no cost.
Yes, Zero-K is completely free with no purchase price, subscription, or in-game currency.
No, Zero-K is a real-time strategy video game, not business software; it is included here as a notable free, open-source title.
Zero-K is built on the Spring engine, an open-source engine originally created for games in the Total Annihilation style.
Yes, Zero-K launched on Steam on April 27, 2018, and is also available directly from the project's own client.
Zero-K is developed by a volunteer open-source community rather than a commercial game studio or publisher.
Zero-K supports Windows and Linux.
No, Zero-K explicitly has no in-game currency, microtransactions, or pay-to-win mechanics.
PlanetWars is a persistent, competitive online campaign in Zero-K where the outcomes of individual matches affect an ongoing meta-game across the player community.