Kusama is a permission-less blockchain network that acts as Polkadot’s canary network, letting teams deploy and test cutting-edge upgrades in a live, value-bearing environment.
Kusama is an independent, public blockchain that shares much of Polkadot’s codebase and design while purposefully lowering the barriers for rapid experimentation. Developers use it to trial new features, parachains, and governance mechanisms under real economic conditions before, or instead of, deployment to Polkadot. The network remains fully sovereign, community-governed, and open to anyone who is willing to "expect chaos."