Permissionless
A system anyone can use or build on without asking a gatekeeper. No application, no allowlist, no approval step. If you meet the protocol's on-chain rules, you are in. The opposite of permissioned.
Also known as: permissionless access
Permissionless means the protocol does not decide who gets to participate. If you can write the transaction and pay the fee, the contract executes it the same as it would for anyone else. There is no sign-up, no KYC at the protocol layer, no human approving your access. This is one of the core properties that separates a real decentralised system from a company with a token: a permissioned system has someone who can say no, and a permissionless one does not.
The word gets used loosely, so it pays to check where the permission actually sits. A project can run a permissionless token contract while gatekeeping the thing that matters: the inference endpoint behind a closed beta, the launchpad behind an approval queue, the “decentralised” network whose nodes are all run by the foundation. OYM reviews look for the permission boundary, the point where someone still has to let you in, because that is usually where the decentralisation claim quietly breaks.
Genuinely permissionless access is also what makes censorship resistance possible. If no entity can refuse your transaction, no entity can be leaned on to refuse it for you. That property is worth more in some contexts (uncensorable inference, open markets) than others, and it always trades against the ability to enforce rules, which is why most “permissionless” systems still keep a few permissioned levers and are worth reading carefully.