Open Source Alternatives to ksqlDB

A stream processing database that allows users to process real-time data streams using SQL syntax. It enables the creation of real-time applications by collecting, enriching, and serving queries on data streams and tables within Kafka. The product supports both push queries for continuous subscriptions to changing results and pull queries for point-in-time lookups. It includes features such as user-defined functions via Java and embedded connectors for moving data in and out of the system. It is available as a fully managed service within Confluent Cloud or can be deployed as part of a data architecture to reduce infrastructure complexity for development teams.

Whether you want to cut software costs or escape vendor lock-in, these open source alternatives to ksqlDB give you an option you fully own. You can self-host them, so your data stays on infrastructure you control. This page lists 1 open source alternative to ksqlDB. The most popular is Timeplus Proton. It uses the Apache-2.0 license and ships an official Docker image.