Starsector is a game of space combat, fleet management, trade, and role-playing. Pilot a ship and command a fleet through intense tactical combat while exploring, trading, battling, and leveling-up in an open-ended sandbox campaign set in a lost sector of the galaxy. Explore distant star systems. Trade goods and loyalty among competing factions. Beware of ruthless pirates while evading tariff patrols. Assemble your fleet for trade or battle while upgrading and modify your starships, then fight your enemies! Forge your destiny and steer the fate of the human race 6000 light-years from Old Earth.

The game itself has minimal plot, and the player is involved in very few story moments. The player is instead intended to create their own story. Lead developer Alexander Mosolov has stated that the player is intended to uncover the setting's backstory as they travel throughout the world. The game takes place in the far future, after humanity developed faster-than-light travel using transport gates, which acted as wormholes. For many years, this method of travel created a golden age for humanity, which took place under a governing political entity known as the Domain. However, exactly 206 years prior to the game's start, all transport gates abruptly ceased to function and humanity was plunged into a dark age where piracy went rampant and splintering factions began to form and exert their influence. This event is referred to as "the collapse". In the sector, a region of space in the Milky Way galaxy where the game takes place, there are various different factions that have taken hold and reached a strategic stalemate, with no faction being able to win. [8] These factions are: