Arroyo vs Materialize

Arroyo is an open-source distributed engine for processing stateful computations on data streams, with sub-second results. Users build streaming pipelines in analytical SQL, including complex queries, windows and joins. Arroyo supports checkpointing for fault tolerance and recovery, exactly-once processing, and horizontal and vertical rescaling; it says the engine can handle millions of events per second. Its connectors include Kafka, Kinesis, MQTT, MySQL, Postgres, Redis, Delta Lake, HTTP and WebSocket, among others. It reads and writes JSON, Avro, Parquet, text and binary, and includes more than 300 SQL functions. Rust scalar, aggregate and asynchronous user-defined functions can extend SQL. The web UI supports connection management, query development and testing, and pipeline monitoring; pipeline management is also available through a REST API. Single-node clusters are intended for development and testing, while production deployments use a distributed cluster with Arroyo’s scheduler or Kubernetes. It is Apache 2.0 licensed, free at free, and self-hostable.

Materialize is a live data layer for apps and AI agents that uses SQL to create up-to-the-second views. Rather than rebuilding query results from scratch as data arrives, it updates them incrementally. Connected sources appear as continually updating tables with sub-second freshness. SQL features include multi-way, lateral, and outer joins, recursive SQL, and SUBSCRIBE, which streams query-result changes over a standard Postgres connection.

Materialize is wire-compatible with PostgreSQL and supports clients and tools that work with PostgreSQL. Listed integrations include PostgreSQL, MySQL, SQL Server, CockroachDB, Kafka, Model Context Protocol, dbt, and webhooks such as EventBridge and Segment. Transformed updates can go to downstream systems including Kafka and Apache Iceberg. It is available as managed Cloud, self-managed Kubernetes software, and a Docker-based local development Emulator. The free self-managed Community Edition is limited to 24 GiB memory and 48 GiB disk. Cloud On-Demand is $1.50 a month, with usage-based compute, storage, and networking; Cloud Capacity is $1.50 a year, with storage and networking billed separately.