The Functional Source License (FSL) is a source-available non-compete license that converts to Apache 2.0 or MIT after one year. It is designed for companies that want to make their core products as Open Source as possible without jeopardizing their business. FSL provides everything a developer needs to use and learn from your software.
FSL’s immediate predecessor is the Business Source License. BUSL’s time-based approach is great, but the Additional Use Grant is a serious flaw, because it creates too much variability. Each implementation of the BUSL is essentially a new license, so compliance departments have to separately review every case, which greatly slows adoption. FSL is an evolved BUSL that (we hope) has a better chance of catching on.