Open-source alternatives to Realm Js

CoreStore is a type-safe Swift interface and persistence wrapper for managing local data storage and object graphs using the Core Data framework. It functions as an atomic persistence manager that executes data updates within transactional blocks to ensure changes are either fully saved or rolled back to prevent state corruption. The project provides a dedicated framework for performing sequential schema migrations through defined version chains and a type-safe object mapping system for importing external JSON data into persistent entities using Swift protocols. It includes a data binding la

This project is a client-side software development kit for iOS and macOS applications that integrates mobile software with a cloud-based backend. It functions as a mobile backend as a service interface, enabling developers to manage user authentication, cloud data persistence, and synchronization without the need to maintain server-side infrastructure. The framework is designed for offline-first development, utilizing a local datastore to cache application state and ensure functionality during periods of network disconnection. It features an automated synchronization engine that queues pendin

Couchbase Lite for iOS is an embedded NoSQL database engine designed for native mobile and desktop applications. It functions as a library within the application process, providing local document storage and structured querying capabilities that allow software to remain fully functional and responsive without an active internet connection. The library distinguishes itself through a replication engine that synchronizes local database changes with a central server to maintain consistent state across multiple devices. This synchronization process utilizes a delta-based protocol to transmit only

Realm Kotlin is a local, object-oriented NoSQL database engine designed for Kotlin Multiplatform applications. It enables developers to persist structured application data directly as objects, eliminating the need for traditional relational table structures while ensuring information remains accessible during offline periods. The library distinguishes itself through a compiler-plugin-based architecture that maps standard language classes to database models at compile time. It utilizes zero-copy memory mapping and a lazy-loading query engine to manage data efficiently, while a shared C++ core

Instant is a real-time backend as a service and relational graph database designed to synchronize data across clients automatically. It functions as a data synchronization layer that provides authentication, permissions, and relational data storage for web and mobile applications. The platform includes an optimistic UI framework that updates local interfaces immediately during writes and handles automatic server rollbacks. It also features a real-time presence system to broadcast transient user states, such as cursor positions and online status, to other connected clients. The system manages

This is a backend-as-a-service SDK that connects web and mobile applications to a suite of cloud services. It provides a unified interface for managing user identity, executing serverless logic, and handling cloud object storage. The toolkit is characterized by its real-time data synchronization, which allows NoSQL document data to stay consistent across multiple clients with built-in offline persistence. It facilitates secure user access through a variety of identity providers and manages serverless function invocation to execute backend logic in response to HTTPS requests or database events

This is a Backend as a Service SDK for Apple platforms, providing a collection of libraries that connect iOS and macOS applications to cloud databases, authentication services, and serverless infrastructure. It serves as a developer kit for integrating real-time data synchronization, file storage, and push notifications into native apps. The SDK is distinguished by its generative AI integration, which routes text and multimodal prompts between on-device models and cloud-hosted large language models. It further differentiates itself with a specialized app distribution tool for managing pre-rel

Electric is a Postgres data synchronization engine and replication proxy designed to enable local-first software. It replicates data from Postgres databases to client-side stores in real time using logical replication, allowing applications to maintain a local embedded database for offline access and low-latency updates. The system distinguishes itself by using shapes to filter and authorize specific subsets of database rows and columns before streaming them to clients or edge workers. It further supports multi-user collaboration by integrating a conflict-free replicated data type framework t

ShareJS is a collaborative document database and synchronization engine designed for real-time shared state management. It provides an operational transform sync engine to enable simultaneous editing of plain-text and JSON data, and a RESTful synchronization API for managing document states via HTTP. The system features an offline-first data sync layer that queues local modifications while disconnected and automatically pushes edits upon reconnection. It also includes a middleware access control layer that intercepts database requests to enforce security policies and perform request rewriting

Jazz is a local-first relational database and synchronization framework designed for offline-capable applications. It functions as a reactive state management system that treats database records as the primary source of truth, automatically updating user interfaces in real time as underlying data changes. The project distinguishes itself through a collaborative data synchronization model that utilizes row-level versioning to track branching edit histories. It implements a security engine based on identity-claim row security, which enforces granular permissions on individual records, and suppo

linq2db is a type-safe object-relational mapper that translates LINQ expressions into optimized SQL queries for multiple database providers. It functions as a database mapper that links classes to tables and includes a SQL query builder and a command-line schema tool for generating data classes from existing databases. The project provides high-performance bulk data processing for inserting and loading large volumes of records via batch or binary copy methods. It also supports advanced SQL operations, including window functions, common table expressions for recursive hierarchical querying, an

Realm-Cocoa is a NoSQL mobile database engine and reactive object database designed for local data storage on mobile devices. It serves as a non-relational alternative to Core Data and SQLite, storing data as objects rather than tables. The system functions as an encrypted local store that protects sensitive application data using encryption. It provides reactive data synchronization, allowing application objects and user interfaces to update automatically when the underlying database changes.

Realm Java is a NoSQL mobile object database and reactive database engine. It provides a persistent local data store that saves native objects directly to disk, replacing traditional SQL storage and object-relational mapping layers. The system functions as a real-time data synchronizer, coordinating local database changes with a cloud backend across multiple devices. It integrates a reactive engine that uses change listeners and asynchronous event streams to automatically update user interfaces when underlying data changes. The project covers object-oriented data modeling, CRUD operations, a

Horizon is a realtime API server and RethinkDB backend designed to push database changes instantly to front-end clients. It utilizes a WebSocket data streaming API to synchronize data between the database and user interfaces without requiring manual polling. The project integrates an OAuth identity manager for verifying user identities through third-party providers and a role-based access control system to define granular permissions for viewing or modifying database documents. It is delivered as a containerized backend framework, allowing the server and its dependencies to be deployed as a p

This project is a collection of reference implementations, sample code, and starter kits for integrating Firebase backend services into web applications using the JavaScript SDK. It serves as a practical guide for bootstrapping projects with cloud-hosted authentication, databases, and serverless logic. The repository provides specific examples for implementing real-time data synchronization, user identity management, and event-driven cloud functions. It also includes reference code for using local service emulators to test cloud functionality on a local machine before production deployment.

Bun is a type-safe object relational mapper for Go that prioritizes SQL-first query construction and result mapping. It functions as a programmable SQL query builder, a database connection manager, and a tool for mapping database tables to Go structs. The project distinguishes itself through a multi-dialect SQL support system, allowing a single codebase to interact with different database engines via a consistent interface. It includes a built-in database observability tool for query interception, distributed tracing, and logging, as well as a schema migration tool for versioning structural c

SQLite.swift is a type-safe Swift wrapper and object-relational mapping layer that provides a bridge for interacting with SQLite databases. It functions as a database driver that allows for embedded database management and local data persistence within Swift applications. The project distinguishes itself through a type-safe expression builder that verifies SQL statement syntax and intent at compile time. It includes specialized support for high-performance text matching via full-text search integration and provides mechanisms for securing sensitive data through database encryption. The libra

Kysely is a TypeScript SQL query builder that provides a type-safe interface for constructing and executing database queries. It functions as a database layer that ensures schema compliance and prevents runtime errors by using a fluent interface and a programmable way to build complex SQL statements. The project features a type-safe database layer capable of inferring return types and aliases from SQL selections and joins. It also includes a SQL migration manager to track and apply schema changes across different environments to keep database versions synchronized. The toolkit covers relatio

React-admin is a framework for building data-driven administrative interfaces that connect to REST or GraphQL backends. It provides a comprehensive suite of tools for managing the full lifecycle of administrative applications, including resource-oriented routing, declarative form scaffolding, and context-driven state management. By utilizing a modular adapter-based architecture, the framework abstracts backend communication, allowing developers to build consistent CRUD interfaces that handle data fetching, authentication, and synchronization automatically. The project distinguishes itself thr

WatermelonDB is an offline-first data synchronization engine and reactive database library designed for mobile and web applications. It provides a persistent storage layer backed by SQLite, enabling applications to maintain full functionality and data consistency while operating without an internet connection. The framework distinguishes itself through a reactive data binding system that automatically updates user interface components whenever underlying database records change. It utilizes schema-driven model mapping to generate type-safe interfaces and employs lazy object materialization to

Drift is a type-safe SQL persistence library and relational mapper that provides a structured way to map database tables to classes and execute SQL queries with build-time validation. It functions as a type-safe query builder and a wrapper for SQLite and PostgreSQL, eliminating manual result set parsing by binding query outputs to native objects. The project distinguishes itself through a build-time code generation system that produces type-safe APIs and validates raw SQL statements against database versions before execution. It features reactive query streaming, which transforms SQL queries

Prisma Client Rust is an object-relational mapping tool and database query builder designed for Rust applications. It functions by reading database schema definitions during the build process to generate strongly typed client code, ensuring that data structures are validated at compile time to prevent runtime errors. The project distinguishes itself through its use of compile-time schema introspection and a trait-based query builder, which together enforce type safety across all database interactions. By mapping raw database rows directly into native Rust structures, it provides a consistent

Mikro-ORM is a TypeScript-based object-relational mapping system that provides a unified persistence layer for Node.js applications. It translates TypeScript entities into relational or document-based database schemas, supporting a variety of engines including PostgreSQL, MySQL, MariaDB, MS SQL Server, SQLite, and MongoDB. The project implements the data mapper pattern to decouple in-memory domain models from the database persistence layer. It utilizes a unit of work pattern to track entity changes in memory and commit them in a single coordinated database transaction. The library covers com

MyBatis-Flex is an object-relational mapping framework for Java that extends MyBatis with a fluent API and automated CRUD operations. It provides a data access suite featuring an automatic CRUD data mapper, a type-safe SQL query builder, and a row-based query engine for manipulating records without predefined entity classes. The framework includes a multi-dialect SQL translator that converts generated syntax across different database engines, such as MySQL, PostgreSQL, and Oracle. It further distinguishes itself by offering annotation-free entity mapping using runtime reflection and naming co

Isar is a type-safe, ACID-compliant local NoSQL document store designed for high-performance data storage and retrieval. It functions as an embedded database engine that persists large datasets on-device while ensuring transactional integrity through automatic rollbacks of failed write operations. The project distinguishes itself by validating database queries at compile time using static typing to prevent runtime errors. It incorporates a full-text search engine with specialized indexing for efficient keyword and phrase matching and utilizes parallel execution across multiple isolates to pre

Content is a file-based content management engine that transforms Markdown and JSON files into structured data for use within web applications. It functions as a static site content engine, parsing local file systems into queryable collections while providing a library for integrating interactive components directly into text documents. The framework distinguishes itself by treating the local file hierarchy as the primary source of truth for application routing and navigation. It enables developers to embed dynamic UI elements directly into text files and provides a visual interface for editi

Prisma Client is a database client for Node.js and TypeScript applications that provides a type-safe interface for interacting with relational databases. It functions as an object-relational mapper that translates declarative schema definitions into strongly typed query interfaces, ensuring that database operations align with the underlying data structure. The library distinguishes itself by generating type definitions directly from a schema model, which enables static analysis and IDE autocompletion during development. By abstracting database interactions into a unified query language, it st