Estuary vs Kafka Streams

Estuary is a managed data integration platform for combining change data capture, batch, streaming, and app synchronization for analytics, operations, and AI. It supports transformations while data is moving, using SQL, Python, or TypeScript, and describes delivery as exactly once with end-to-end latency under 100 milliseconds. More than 200 prebuilt connectors cover databases, warehouses, SaaS apps, and cloud platforms, including Snowflake, BigQuery, Kafka, MySQL, and PostgreSQL. Customers can store data in their own cloud bucket for a duration they choose, and select public, private, or Bring Your Own Cloud deployment. Estuary lists SOC 2 Type II, HIPAA, HITECH, CCPA, and GDPR among its compliance standards, and says data is encrypted in transit and at rest. It is available through API, self-hosted, and web options. The indefinite free tier is limited to 10 GB per month and two concurrent connector instances; paid plans start at $100 a month.

Kafka Streams is a free client library for building applications and microservices that use data stored in Kafka clusters. It processes Kafka data with event-time handling, windowing, and real-time queries of application state. The Streams DSL provides operations such as mapping, filtering, joins, and aggregations, while the Processor API supports custom processors and state stores. Fault-tolerant local state supports stateful work such as windowed joins and aggregations, and the library offers exactly-once processing semantics. Applications can run on one machine or scale across multiple machines, and can be deployed in containers, virtual machines, on bare metal, or in cloud environments. Kafka Streams uses Kafka as its internal messaging layer and does not require a separate processing cluster. It supports Java and Scala and integrates with Kafka security features for encryption in transit, client authentication, and authorization. The software is licensed under Apache License 2.0. The Apache Software Foundation says it does not sell its software or provide formal or commercial support for its packages; project communication is available through community mailing lists.