Arroyo – Write SQL on streaming data
Hey HN, Arroyo is a modern, open-source stream processing engine, that lets anyone write complex queries on event streams just by writing SQL—windowing, aggregating, and joining events with sub-second latency. Today data processing typically happens in batch data warehouses like BigQuery and Snowflake despite the fact that most of the data is coming in as streams. Data teams have to build complex orchestration systems to handle late-arriving data and job failures while trying to minimize latency. Stream processing offers an alternative approach, where the query is compiled into a streaming…
Arroyo – Write SQL on streaming data launched on June 6, 2023 with 115 votes, #427 of 4,655 launches that month and more than 95% of that year's launches. The site was still online in September 2026, 3 years on.
In plain words
Arroyo is an open-source stream processing engine that lets data teams write SQL queries on event streams to perform windowing, aggregating, and joining with sub-second latency. It compiles queries into streaming programs that continuously update as new data arrives, eliminating the need for complex batch orchestration systems. The tool is designed for data teams processing real-time event streams who want low-latency results without building custom infrastructure for handling late-arriving data and job failures.
written from the facts on this page · September 2026
From the sources
Distributed stream processing engine in Rust. Contribute to ArroyoSystems/arroyo development by creating an account on GitHub.
In the maker’s words, at launch
Hey HN, Arroyo is a modern, open-source stream processing engine, that lets anyone write complex queries on event streams just by writing SQL—windowing, aggregating, and joining events with sub-second latency. Today data processing typically happens in batch data warehouses like BigQuery and Snowflake despite the…
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