The Ontology Lookup Service (OLS) is a repository for biomedical ontologies that aims to provide a single point of access to the latest ontology versions. You can browse the ontologies through the website as well as programmatically via the OLS API. In 2023 OLS was updated to scale better and with a new user interface. OLS is used within life sciences but also in the fields of chemistry and engineering. Code is available under an Apache 2.0 licence.