Closure Wiki is a fan-made database and wiki resource dedicated to Arknights, providing players with an organized place to explore information about the game. Its coverage includes operators, enemies, operations, items, modules, outfits, medals, summons, avatars, and CG galleries. The site also features sections for game modes, including Integrated Strategies and Stronghold Protocol, with a dedicated Stronghold Protocol: Alliance page. Additional tools and resources include the Closure Story Reader and Closure Stage Simulator, supporting visitors who want to browse story content or explore stages.

The homepage offers links to the latest operators on the Chinese and global servers, along with server-time information and daily and weekly reset timers. It also points users toward recommended external Arknights resources, including wikis, story tools, and archives. Visitors can join the Closure Wiki Discord to follow updates, see datamines, or share feedback and questions. Closure Wiki describes itself as a hobby project and states that it is not affiliated with Hypergryph or Yostar; Arknights and its related assets belong to their respective owners.