Project Spotlight: Flowtide

June 27, 2025 by .NET Foundation Board

This month’s open source spotlight shines on Flowtide.NET — an exciting and ambitious project that brings SQL-based stream processing into the heart of the .NET ecosystem.

What is Flowtide.NET?

Flowtide.NET is a high-performance SQL streaming engine built entirely in .NET. It enables developers to define continuous data processing workflows using SQL syntax, ideal for scenarios where data is constantly flowing in and immediate insights or transformations are required.

Inspired by systems like Apache Flink and ksqlDB but designed to work seamlessly in .NET environments, Flowtide.NET empowers developers to:

  • Write declarative SQL queries that run continuously on data streams
  • Perform real-time analytics, filtering, joins, and aggregations
  • Integrate with Apache Arrow, Kafka, and other modern data pipelines
  • Embed stream processing logic directly in C# applications or services

Whether you’re working on event-driven systems, IoT telemetry, financial tickers, or log analysis pipelines. Flowtide.NET brings powerful, low-latency stream processing directly into your .NET stack.

Dive into the docs: Flowtide.NET Documentation

Why it matters to the .NET Foundation community

Flowtide.NET brings a whole new category of data processing capabilities to .NET developers. As an open-source project under the .NET Foundation, it provides the following:

  • Innovation in Data Engineering – Fills a critical gap for real-time data stream processing within .NET
  • Ecosystem Extension – Integrates with existing open standards like Apache Arrow, helping .NET stay interoperable in modern data infrastructure
  • Developer Productivity – Enables writing complex data workflows using familiar SQL rather than bespoke imperative code
  • Community Collaboration – Offers a new platform for contributors to explore distributed systems, high-throughput data flows, and advanced SQL processing, all within .NET

Flowtide.NET is a shining example of how the .NET open-source community continues to push boundaries and explore new frontiers.

Explore the code, try out a demo, or get involved at github.com/koralium/flowtide.