Open-source alternatives to NuDB

Cassandra is a distributed NoSQL database and wide-column store designed for high availability and linear scalability. It functions as a fault-tolerant distributed system that utilizes an LSM-tree storage engine to optimize write throughput and manage massive datasets. The system is a CQL-compliant database, using a structured query language to manage and retrieve tabular data stored across multiple nodes. It organizes information into rows and columns based on a flexible schema and primary keys. The project provides capabilities for horizontal database scaling, distributed data partitioning

One advanced and mature open-source MPP (Massively Parallel Processing) database. Open source alternative to Greenplum Database.

CouchDB is a NoSQL document database that stores data as flexible documents and exposes a RESTful API for data management over HTTP. It functions as a distributed document store, synchronizing and replicating data across multiple nodes to ensure high availability and consistency. The system includes a full-text search engine that transforms database records into queryable documents, supporting sorting and pagination. Data synchronization is handled via multi-master replication, which exchanges revision histories to maintain consistency across distributed nodes. The database utilizes multi-ve

HBase is a distributed, wide-column NoSQL store and big data storage engine designed for sparse datasets. It functions as a scalable columnar database built on top of the Hadoop Distributed File System to provide real-time read and write access to massive volumes of structured and unstructured data. The system acts as a cross-language database gateway, offering connectivity through native remote procedure calls, REST, and Thrift interfaces. It distinguishes itself through a master-worker coordination model that enables horizontal scaling and fault tolerance across a cluster. The project cove

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

ShardingSphere is a distributed SQL database middleware that provides sharding, read-write splitting, and distributed transaction management for relational databases. It functions as a layer that intercepts SQL queries to distribute data across multiple physical database instances for horizontal scaling. The project is distinguished by its ability to operate as either a standalone transparent database proxy or via direct integration as a JDBC driver. It features a SQL dialect translator that parses queries into abstract syntax trees to convert syntax between different database engines, enabli

ApeCloud's Data Transfer Suite, written in Rust. Provides ultra-fast data replication between MySQL, PostgreSQL, Redis, MongoDB, Kafka and ClickHouse, ideal for disaster recovery (DR) and migration scenarios.

KubeBlocks is a Kubernetes Operator designed to manage a variety of databases and streaming systems, including MySQL, PostgreSQL, MongoDB, Redis, RabbitMQ, RocketMQ, and more, within Kubernetes environments.

This project is a multi-model database system designed to store and manage information as documents, graphs, and key-value pairs within a single engine. It functions as a graph database and knowledge graph platform, providing the infrastructure to build, query, and visualize structured data models. By integrating vector search capabilities, the system serves as a vector database that supports retrieval-augmented generation for artificial intelligence applications. The platform distinguishes itself through a unified query language that allows users to perform document lookups, graph traversals

SpiceDB is a distributed permission store and relationship-based access control system. It provides a scalable database for storing and querying fine-grained authorization relationships, implementing a consistency model inspired by Google Zanzibar to manage access rights across large-scale applications. The system uses a dedicated schema language to define the rules and logic governing how relationships translate into permissions independently of application code. It functions as a pluggable authorization engine that persists relationship tuples in external relational databases such as Postgr

Redis and Valkey module that implements the token-bucket algorithm as a native command for high-performance rate limiting

Single-binary observability, time-series database, and built-in dashboard for Raspberry Pi, edge devices, and local metrics.

C++11 wrapper for the LMDB embedded B+ tree database library.

chDB is an in-process OLAP SQL Engine 🚀 powered by ClickHouse

A distributed key-value store. On Disk. Able to grow or shrink without service interruption.

Chroma is a specialized vector database designed to index and retrieve high-dimensional data representations for semantic similarity search. It functions as a comprehensive platform for information retrieval, enabling the storage and management of unstructured documents alongside structured metadata. By mapping data into numerical representations, the system facilitates rapid similarity lookups across large datasets. The platform distinguishes itself through a hybrid search infrastructure that combines dense vector embeddings with sparse keyword and regular expression matching to balance sema

Simply ACID* key-value database. At the medium or even low latency it tries to provide greater throughput without losing the ACID properties of the database. The database provides the ability to create record headers at own discretion and use them as transactions. The maximum size of stored data is limited by the size of the computer's RAM.

ClickHouse is a high-performance, columnar analytical database designed for real-time query execution and large-scale data aggregation. It functions as a distributed data warehouse capable of processing petabytes of information, while also providing an embedded engine that integrates directly into applications for native query capabilities without external dependencies. The system is built to handle high-throughput ingestion and complex analytical workloads, delivering millisecond-level latency for interactive dashboards and operational monitoring. The platform distinguishes itself through ad

C++ client library for ClickHouse

SpacetimeDB is a stateful, real-time database platform that executes application logic directly within the database engine. By unifying data storage and business logic, it allows developers to build applications where state transitions are processed through atomic, server-side functions. The platform maintains persistent connections to stream incremental updates to clients, ensuring that local caches remain synchronized with the server state at all times. The platform distinguishes itself by generating type-safe client interfaces directly from server-side schema definitions, ensuring consiste

Cockroach is a distributed SQL database designed to scale horizontally across multiple nodes while maintaining strict ACID compliance and global data consistency. It functions as a relational database engine that automatically partitions data into ranges, rebalancing them across a cluster to accommodate growing storage and throughput requirements. By utilizing a distributed consensus protocol, the system ensures that all nodes agree on the order of operations, providing fault tolerance and continuous availability even in the event of hardware failures. The system distinguishes itself through

Pebble is an embedded key-value storage engine written in Go, designed as a library that provides durable, write-optimized data persistence directly within applications. It organizes data using a log-structured merge-tree (LSM-tree) structure, where writes are first buffered in an in-memory skiplist memtable and persisted to a write-ahead log before being flushed to block-based SSTable files on disk. The engine supports atomic batch commits, configurable write synchronization, and automatic background compaction that merges and rewrites sorted runs to reclaim space and maintain read performanc

immudb is a tamperproof database that maintains an immutable record of entries using cryptographic commit logging. It ensures verifiable database integrity by utilizing Merkle trees to generate membership and consistency proofs that detect unauthorized data alterations. The system employs a multi-model storage engine that unifies key-value, document, and relational data structures within a single immutable backend. It provides compatibility with the PostgreSQL wire protocol, allowing it to integrate with standard SQL clients, ORMs, and database tools. The project covers broad capabilities in