Open-source alternatives to Faust

Apache Flink is a distributed processing engine designed for both high-throughput, low-latency data streams and finite batch workloads. It functions as a stateful stream processor and a SQL stream processing engine, providing a unified runtime to execute relational queries and event-based transformations. The system is distinguished by its ability to manage persistent operator state to ensure exactly-once processing guarantees and consistency during failures. It features specialized capabilities for complex event processing to detect temporal patterns and handles out-of-order events using eve

Arroyo is a high-performance stream processing platform built in Rust. It executes continuous SQL queries on streaming data with event-time semantics, enabling accurate windowed aggregations, joins, and stateful computations on unbounded event streams. The platform uses native Rust execution for high throughput and low latency, with periodic checkpointing for exactly-once fault tolerance and horizontal scaling across distributed workers. The system integrates deeply with Kafka for reading and writing topics with exactly-once delivery and supports change data capture (CDC) from MySQL and Postg

NATS Server is a high-performance, lightweight messaging system designed for cloud-native applications, edge computing, and distributed microservices. It functions as a distributed publish-subscribe broker that routes messages using hierarchical, dot-separated subject strings, enabling decoupled communication between services without requiring centralized broker lookups. The system supports core messaging patterns including asynchronous publish-subscribe, request-reply, and load-balanced queue processing. The platform distinguishes itself through a decentralized architecture that eliminates t

Uptrace is an OpenTelemetry-based observability platform designed to collect, store, and analyze distributed traces, metrics, and logs. It functions as a centralized logging backend, a distributed tracing system, and a metrics engine to monitor application performance and system health. The platform is distinguished by AI-powered operational capabilities, allowing users to query telemetry data and manage monitoring dashboards using natural language. It specifically includes specialized monitoring for generative AI pipelines, tracking token usage and response quality for LLM interactions and r

Riemann is a Clojure-based event stream processor and real-time analytics engine. It functions as a network telemetry pipeline and extensible event router that ingests, transforms, and routes event data from distributed systems. The system uses a domain-specific language to compute metrics and statistical patterns over continuous streams, enabling network trend analysis and real-time alerting. It supports dynamic plugin loading from the classpath and allows for live configuration reloading without interrupting active event streams. Capabilities include centralized telemetry aggregation, even

Garnet is a multi-threaded in-memory database and distributed key-value store. It functions as a high-performance remote cache store that implements the RESP wire protocol to maintain compatibility with existing Redis clients and libraries. The project is distinguished by a shared-memory architecture that enables parallel request processing across multiple cores for sub-millisecond latency. It features a tiered storage system that automatically offloads colder data from system memory to SSD or cloud storage layers, and includes a specialized vector search database for high-dimensional similar

YDB is a distributed SQL database and analytical engine designed for horizontal scalability and strong consistency. It functions as a multi-model system that supports transactional and analytical workloads through a distributed architecture providing serializable ACID transactions. The system is distinguished by its broad protocol compatibility, implementing the PostgreSQL wire protocol for standard SQL drivers and the Kafka protocol for messaging and streaming. It further serves as a vector database, supporting vector indexes and approximate nearest neighbor searches for semantic search and

Akka.NET is an actor model framework used for building concurrent and distributed applications. It functions as a distributed computing platform and state manager that enables isolated actors to communicate via asynchronous message passing, ensuring thread-safe state management without manual locks. The project is distinguished by its decentralized coordination capabilities, including a distributed state manager that uses sharding and dynamic rebalancing to maintain high availability. It incorporates an event sourcing engine that persists state as a sequence of events in an append-only log an

Pinot is a distributed, columnar analytical database designed for high-concurrency, low-latency query processing. It functions as a real-time OLAP datastore, enabling interactive, user-facing analytics by ingesting and querying massive datasets from both streaming and batch sources. The system architecture relies on a centralized controller for cluster coordination and a distributed segment-based storage model to ensure horizontal scalability. The platform distinguishes itself through a hybrid ingestion pipeline that unifies real-time event streams and historical batch data into a single quer

Toon is a data serialization library and toolkit designed to convert complex objects into compact, human-readable formats optimized for large language models. By focusing on token efficiency, the library minimizes the context window footprint of structured data through techniques like key folding and tabular layout optimization. It provides a streaming-capable processor that handles the encoding and decoding of hierarchical data while maintaining structural integrity. The project distinguishes itself through its path-aware transformation pipeline and configurable serialization logic, which al

RocketMQ is a distributed messaging and streaming platform designed for building event-driven applications. It serves as middleware to decouple services using publish-subscribe and request-reply patterns, and functions as a transactional messaging system that ensures atomicity by linking message delivery to local transaction outcomes. The platform includes specialized capabilities as a Kubernetes-native message broker for container orchestration environments and an MQTT broker for ingesting event data from mobile applications and hardware terminals. The system covers high-throughput data str

sofa-jraft is a Java implementation of the Raft consensus algorithm. It serves as a distributed consensus engine and linearizable state machine designed to ensure high availability and data consistency across a cluster of nodes. The project provides a replicated key-value store and a coordination engine for managing distributed state. It distinguishes itself through support for multi-group consensus sharding to distribute traffic and a service provider interface that allows for custom log storage and entry encoding implementations. The system covers a wide range of distributed capabilities,

This project serves as a comprehensive technical reference for the architecture and design of data-intensive applications. It provides a structured analysis of the fundamental principles required to build reliable, scalable, and maintainable software systems, covering the core trade-offs inherent in modern data infrastructure. The repository explores the mechanics of distributed data management, including strategies for replication, partitioning, and achieving consensus across multiple nodes. It details the design of storage engines, indexing techniques, and transaction management models, whi

GreptimeDB is a distributed, open-source time-series database built for unified observability. It stores and queries metrics, logs, and traces together in a single columnar engine, supporting both SQL and PromQL for analysis. The database is designed as a Kubernetes-native operator with a decoupled compute and storage architecture, enabling horizontal scaling and multi-region deployment. What distinguishes GreptimeDB is its role as a multi-protocol ingestion gateway, accepting data through OpenTelemetry, Prometheus Remote Write, InfluxDB, Loki, Elasticsearch, Kafka, and MQTT protocols without

This project is a comprehensive educational resource and curriculum focused on site reliability engineering, distributed systems, and infrastructure operations. It provides technical guides, a systems engineering course, and instructional manuals designed to teach the principles of managing large-scale computing environments. The curriculum covers high-level architectural design for scalability and resilience, including fault-tolerant infrastructure, high-availability patterns, and microservices decomposition. It emphasizes the practical application of site reliability engineering through the

Feast is an open-source feature store for machine learning that provides a central platform for defining, storing, and serving features across both training and inference workflows. It operates as a declarative system where feature definitions are written as code in Python files, synchronized to a central registry, and made available for low-latency online retrieval or point-in-time correct historical joins for training datasets. The project abstracts storage behind a pluggable architecture, allowing offline and online backends to be swapped without changing retrieval logic, and coordinates ma

node-redis is a Node.js client and database driver for interacting with Redis key-value stores. It functions as a connection manager and data iterator, allowing applications to execute database commands and manage atomic transactions on a remote server using asynchronous JavaScript. The project provides specialized capabilities for handling large datasets through an asynchronous interface and supports connection pooling to isolate blocking operations. It includes support for client-side caching and token-based authentication via Entra ID. The driver covers a broad range of operational areas,

Rx.NET is a reactive programming framework and library for the .NET ecosystem used to compose asynchronous and event-based programs. It provides an observable data stream API that treats live sequences of information as collections, allowing developers to coordinate asynchronous event workflows using a declarative syntax. The project functions as an extension of language integrated query patterns to asynchronous streams. This allows for the filtering and transformation of asynchronous notifications and event sequences through the application of query operators. The framework covers asynchron

Octosql is a federated SQL query engine, data transformer, and streaming SQL processor. It allows users to execute single SQL statements across multiple disparate data sources, including different database types and file formats, to merge and transform results into a unified set. The system distinguishes itself by treating CSV, JSONLines, and Parquet files as virtual tables and utilizing a plugin-based architecture to extend connectivity to external storage engines. It functions as a streaming processor for infinite data streams, using watermarks, retractions, and tumbling windows to maintain

Fluvio is a distributed event streaming platform and cloud-native streaming engine designed for collecting, persisting, and replicating real-time data streams across a distributed cluster. It functions as a real-time data pipeline for building stateful workflows that ingest, enrich, and export data between external sources and sinks. The platform is distinguished by its use of WebAssembly to execute compiled modules for in-line data transformations and filtering. This allows for the execution of custom business logic to reshape information in motion without requiring a restart of the cluster.

Kvrocks is a disk-based NoSQL database and distributed key-value store that leverages the RocksDB storage engine to persist large datasets to physical disk. It is designed to be a Redis-compatible database, utilizing the standard Redis communication protocol to ensure interoperability with existing client libraries and tools. The project distinguishes itself by combining a disk-persistent storage model with advanced retrieval capabilities, including vector search for k-nearest neighbor queries, full-text search indexing, and geospatial query execution. It supports distributed clustering with

TiKV is a distributed transactional key-value store designed for horizontal scalability and high availability. It functions as a storage engine that maintains massive datasets across a cluster of physical nodes, ensuring that information remains accessible and consistent even when individual hardware components fail. The system utilizes a consensus-based replication model to synchronize data across nodes, ensuring that all replicas agree on the order of operations. It manages data distribution through a sharding mechanism that partitions large datasets into smaller groups, each governed by in

Redisson is a Java client library for Redis and Valkey that provides a distributed data structure library, a distributed lock manager, and a distributed MapReduce framework. It enables application instances in a cluster to share state through thread-safe collections and objects. The project implements a JCache compliant caching layer for standardized data storage and retrieval. It also functions as a probabilistic data store, providing memory-efficient structures such as Bloom filters and HyperLogLog for high-volume data membership testing. The library covers distributed state management usi

Dynomite is a distributed data sharding layer and key-value storage engine proxy. It functions as a distribution layer that shards and replicates data across multiple nodes, transforming single-server datastores into scalable peer-to-peer systems. The system acts as a multi-datacenter data replicator, synchronizing data between different geographical locations to ensure resilience and high availability during site failures. It manages the distribution of key-value data to enable linear datastore scaling and redundant storage. The project provides capabilities for storage engine sharding and

This project serves as a comprehensive technical guide and framework for building, deploying, and managing event-driven applications. It focuses on serverless architecture development, providing patterns and practices for implementing cloud-native services that execute code in response to triggers without requiring persistent server infrastructure. The repository distinguishes itself by offering a unified approach to polyglot runtime orchestration, allowing developers to manage components written in multiple programming languages within a single project. It emphasizes local cloud emulation, e

FoundationDB is an ACID-compliant distributed transactional key-value store. It functions as a scalable database engine that ensures strict serializability and data consistency across a cluster of servers using a shared-nothing architecture. The system is distinguished by its multi-region replication capabilities, allowing data to be synchronized across different datacenters for high availability and disaster recovery. It utilizes optimistic concurrency control to manage distributed transactions and employs a majority-based coordination system to maintain cluster state. The platform provides

TiKV is a cloud-native distributed transactional key-value store and storage engine. It provides a distributed database designed for horizontal scalability and strong consistency across a cluster of physical nodes. The system uses a Raft-based consensus mechanism to maintain data availability and state synchronization. It ensures ACID compliance for distributed transactions through a two-phase commit workflow and manages data distribution via multi-Raft sharding. The engine handles massive datasets using automated range splitting and cluster load balancing to distribute data across different