# Permissionless Pools A distinctive feature of Spectra Protocol is permissionless pool creation. The protocol allows users to create pools by supplying ERC4626-compatible interest-bearing tokens. Providing liquidity to Spectra offers the opportunity to earn from swap fees while keeping liquidity providers entitled to yield accrual and all sorts of incentives. At the root level, the Spectra protocol is where three market actors converge: \#1 - Actors who anticipate the rates will go up \#2 - Actors who anticipate the rates will go down \#3 - Actors looking to earn fees from the activities of the first two groups.\ \ Those activities come by various names: yield trading, fixed rates, upfront yield, etc. Fundamentally, Spectra applies a fee to every token exchange on the protocol, creating a source of yield for those supplying liquidity. ### Pools on Spectra Pool creation on Spectra is permissionless, meaning there is no voting or human-gated process. Anyone can open a pool with any amount of [ERC-4626 compatible](https://tvl.erc4626.info/) interest-bearing tokens and earn fees from powering all sorts of protocol activities. \ When creating a pool, in addition to supplying the initial liquidity as an interest-bearing token, the user needs to specify its maturity date and target APR—more on this in the [app-help](https://docs.spectra.finance/app-help "mention") section. ### Sources of Yield Liquidity providers in Spectra pools are entitled to the following yield streams originating from: * Pool's swap fees * The native yield of the interest-bearing token token * Principal Token's fixed rate yield * Spectra's native APW emissions to pools * Incentives to pools provided by 3rd parties Plus, any potential rewards emitted by underlying platforms to holders of ERC-4626 tokens. ### Pool Infrastructure Spectra is AMM agnostic. Initially, it leverages battle-tested Curve pool infrastructure to power efficient protocol swaps. ### Future Implementations One limitation of Spectra's current pool model is the expiry date, which means providing liquidity isn't completely passive. The upcoming introduction of the MetaVault model addresses this by enabling automatic liquidity rollovers.