Open-source alternatives to Postgres

LiteDB is a serverless, embedded NoSQL document database for .NET applications. It persists data into a single portable file, functioning as a BSON data store that resides within the application process rather than running as a separate server. The system is ACID compliant, utilizing write-ahead logging to ensure atomic, consistent, isolated, and durable transactions. It includes built-in encryption to provide secure local data storage and protect files on disk from unauthorized access. The project covers object-document mapping to convert classes into document formats, indexed search capabi

Neo4j is a native graph database management system designed to store and query highly connected data using a property-graph model. It provides an ACID-compliant transaction engine that ensures data integrity, supported by a distributed cluster architecture that maintains causal consistency across nodes. Users interact with the system through a declarative query language, which allows for complex pattern matching and path traversal without requiring manual traversal logic. The platform distinguishes itself through its hybrid approach to data retrieval, combining traditional graph-based queries

This project is a distributed, document-oriented database system designed to store information in flexible, hierarchical structures. It supports horizontal scaling through automated sharding and maintains high availability across global clusters using a multi-node replication protocol. By executing multi-document operations as atomic units, the system ensures data integrity and consistency across distributed environments. The platform distinguishes itself by integrating advanced vector-based indexing, which enables semantic similarity searches alongside traditional geospatial and lexical quer

bbolt is an ACID-compliant embedded key-value store for Go applications. It persists all data in a single memory-mapped file on disk, organizing information using B+ trees to facilitate sorted key iteration and efficient range queries. The project distinguishes itself through a hierarchical data organization model, allowing buckets to be nested within other buckets to create a tree-like structure. It employs a single-writer, multi-reader locking mechanism and copy-on-write transactions to ensure serializable isolation and data integrity. The system includes comprehensive data management capa

RocksDB is a high-performance, embeddable persistent key-value library and storage engine based on Log-Structured Merge-trees. It is designed to provide durable storage for large-scale datasets, integrating directly into applications to manage data on flash and RAM-based hardware. The engine is distinguished by its focus on minimizing read and write amplification through multi-threaded compaction and custom memory allocators. It features specialized optimizations for flash storage, including support for zoned block devices, and provides the ability to extend store behavior via external plugin

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

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

goleveldb is an embedded key-value storage database for Go. It provides local data persistence and indexing, allowing applications to store and retrieve information using unique keys without requiring a separate server. The database organizes data using a log-structured merge-tree and persistent indexing in lexicographical order. This structure supports efficient range scans and prefix-based searches. The system includes capabilities for atomic batch writes to ensure data consistency and avoid partial updates. Performance is managed through write-ahead logging, memory-based buffering, and bl

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

ToyDB is a distributed SQL database that provides a system for storing and querying data across multiple nodes. It focuses on maintaining strong consistency and fault tolerance through the implementation of a distributed consensus algorithm. The project distinguishes itself by supporting historical data versioning, enabling time-travel queries to retrieve the state of the database from a specific point in the past. It utilizes multi-version concurrency control to manage ACID transactions and ensure data integrity during concurrent operations. The system covers relational data modeling with t

Sled is an embedded key-value store and ACID-compliant database designed for high-performance data persistence. It functions as a log-structured storage engine that organizes data using B+ trees to support efficient range queries and prefix scans. The engine implements a zero-copy data store model, utilizing epoch-based reclamation to provide direct references to cached values without memory allocations. It distinguishes itself through a combination of write-ahead logging, page cache optimizations to reduce write amplification on flash storage, and serializable transactions for atomic multi-k

This project is an open source relational database management system and SQL database designed for storing and managing structured data. It functions as a relational database for ensuring consistency and reliability, while also operating as a vector database for storing and querying high-dimensional vector embeddings. The system incorporates a columnar storage engine to optimize analytical query processing and large-scale data aggregation. It further enables vector similarity search, allowing users to find similar items by querying vector embeddings. The software covers a broad capability su

SurrealDB is a multi-model database engine designed to store and query document, graph, relational, and vector data within a single ACID-compliant platform. It functions as an AI-native data store, integrating vector search, graph traversal, and machine learning model execution directly into its query layer. By providing a unified declarative query language, the platform eliminates the need for external middleware to synchronize data across different storage models. The platform distinguishes itself through its ability to manage agent memory and complex workflows natively. It allows developer

Redka is a SQL-backed key-value store that implements a Redis-compatible interface. It acts as a relational data bridge, translating non-relational protocol commands into relational queries to provide persistence and ACID transactions using a SQL database backend. The system allows for relational data introspection by exposing internal key-value data as SQL views, enabling direct querying and analysis via relational syntax. It can be deployed as a standalone network server or as an embedded library within a Go application. The project supports a variety of data structures, including strings,

MiniOB is an open-source educational relational database kernel designed for learning the internals of database systems. It implements a dual-engine storage architecture combining B+ Tree and LSM-Tree, supports SQL parsing and query execution, and provides transactional processing with multi-version concurrency control. The system communicates with clients using the MySQL wire protocol and includes a vector database extension for storing and querying high-dimensional vectors. The project distinguishes itself through its comprehensive coverage of core database concepts in a single, learnable c

LevelDB is an embedded database library and persistent storage engine that provides a sorted key-value store. It uses a log-structured merge-tree architecture to map byte arrays to values, running directly within a process to provide storage without the need for a separate server process. The system is distinguished by its use of custom comparison functions to define key ordering, enabling efficient range scans and sequenced lookups. It ensures data reliability through atomic batch execution, consistent snapshot generation, and log-based recovery after failures. The engine covers broad capab

Titan is a distributed graph database and computing engine designed for storing and querying massive datasets of interconnected nodes and edges across multi-machine clusters. It functions as a scalable graph storage layer and transactional store, providing a framework for executing large-scale graph processing jobs and deep traversals. The system is distinguished by its pluggable storage backend, which decouples the graph engine from the physical persistence layer. It utilizes vertex-cut data partitioning to balance processing loads and a set-cardinality property model that allows single prop

RoseDB is an embedded key-value database and log-structured storage engine. It functions as a library-based database that runs within an application process to provide local data persistence without the need for a separate database server. The project implements a Bitcask-style store, utilizing an append-only log format to maximize write throughput and minimize seek time. It ensures data consistency by grouping multiple read and write operations into single atomic units. The storage architecture relies on an in-memory key index for constant-time lookups and uses segment-based file management

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

SQLite is a serverless relational database engine and C-based library that stores data in a single local disk file. It functions as an embedded SQL database, integrating directly into applications without the need for a separate server process. The engine includes specialized capabilities for full-text search indexing and spatial data querying using R-Tree structures for geographic or geometric coordinate ranges. The system provides broad support for SQL data manipulation, database recovery and repair, and change tracking for synchronizing modifications between databases. It also features a

InfluxDB is a high-performance time-series database designed for collecting, storing, and querying time-stamped metrics and event data. It functions as a columnar time-series store and a real-time analytics engine, providing a network-accessible interface for retrieving and analyzing temporal records. The system utilizes a specialized columnar storage format to support high ingestion rates and efficient data retrieval. It incorporates a programmable runtime for executing custom plugins and triggers, including integration for processing and transforming incoming data streams. The platform cov

Sequelize is an object-relational mapping library that provides a unified interface for managing relational data through code. By implementing the Active Record pattern, it maps database tables to application objects, allowing developers to perform standard create, read, update, and delete operations using high-level method calls. The library abstracts complex database interactions by translating these calls into optimized, engine-specific SQL statements, ensuring consistent behavior across different database systems. The project distinguishes itself through a comprehensive suite of tools for

RethinkDB is a distributed, document-oriented database designed to store and manage JSON-formatted data across scalable clusters. It utilizes a custom log-structured storage engine with B-Tree indexing to ensure high-performance disk I/O and data persistence. The system maintains high availability through automatic sharding and replication, employing a primary-replica voting consensus mechanism to handle node failures and ensure consistent cluster operations. A defining characteristic of the platform is its reactive changefeed engine, which allows applications to subscribe to live data update

Lightweight RESTful database engine based on stack data structures

A decentralized, trusted, high performance, SQL database with blockchain features

A rudimentary implementation of a basic document (NoSQL) database in Go

EliasDB a graph-based database.