QuestDB is an open-source time-series database written mainly in Java, with C++ and Rust on performance-critical paths. It ingests large volumes of events and queries them with SQL extended for time series, such as SAMPLE BY and ASOF JOIN. It supports the PostgreSQL wire protocol, InfluxDB Line Protocol and a REST API, and includes a web console. You can run QuestDB yourself with Docker, Kubernetes or on bare metal. The paid Enterprise edition adds high availability, role-based access control, TLS and SSO, and runs on AWS, Azure or GCP, or fully managed inside your own cloud account.
QuestDB is headquartered in London and New York. The core is licensed under Apache 2.0; the Enterprise edition is not open source. When self-hosted in your own datacentre, the location and operation of the data stay entirely with you. Managed variants run on US hyperscalers, so European organisations should check which region is used, or use the Bring-Your-Own-Cloud option.