QuestDB

QuestDB is an open-source time-series database aimed at high-ingest workloads. It is developed by QuestDB and licensed under Apache-2.0, an open-source licence. Queries are written in SQL with time-series extensions such as SAMPLE BY and ASOF JOIN. It can be run self-managed, or through the commercial Enterprise Cloud and Bring Your Own Cloud options. The latest release is 10.0.1, dated 24 August 2026, which sits on a new major version line, so existing users should read the release notes before upgrading. Pricing is not published. The open-source database is free to use, and the enterprise offerings are arranged through the sales team, so buyers who need Enterprise Cloud or a Bring Your Own Cloud deployment will have to ask the vendor for a quotation. QuestDB suits teams that want to keep using SQL for time-series work, such as joining measurements at the nearest preceding timestamp or aggregating by time interval, and that want to start with free open-source software while keeping a commercial route available. The project shows as active, with a release in August 2026. It is a database in its own right rather than an extension to another database.