Permissionless
A network anyone can join, use, or build on without asking a gatekeeper for approval.
A permissionless blockchain is open by default. You don't register or pass a check to send Bitcoin or deploy a smart contract. The protocol treats every address the same, whether it belongs to a person or a bot.
This openness drives much of crypto's growth and its problems. Anyone can launch a token, which fuels both DeFi and outright scams. Contrast it with a permissioned blockchain, where an operator decides who gets in. Permissionless systems lean on code and economics instead of a list of approved members.
Related terms
A closed blockchain where a known operator controls who may join and validate transactions.
TrustlessA system where you rely on code and math instead of trusting a middleman.
DecentralizationSpreading control and data across many independent participants so no single party can dictate or shut things down.