20 open-source projects similar to metowolf/vcards, ranked by shared indexed features. Tags may describe platforms or build tools rather than the same primary purpose. Check each project’s use case, license, and deployment requirements before treating it as a replacement.
Radicale is a self-hosted CalDAV and CardDAV server implemented in Python that enables calendar and contact synchronization across multiple clients using open standards. It stores all data directly on the filesystem in a simple folder hierarchy, eliminating the need for an external database, and automatically tracks every change by committing modifications to a Git repository for version history and backup. The server distinguishes itself through a modular plugin architecture that allows custom Python modules to extend authentication, storage backends, and web interface functionality at start
Yowsup is a protocol library and client framework for implementing WhatsApp clients. It provides an interface for sending and receiving multimedia messages, managing group chats, and handling account registration. The project features a modular system for building communication stacks that process encrypted data and network connections. It includes a protocol library to manage messaging, presence states, and account registration, alongside an interactive command line interface for interacting with users and managing contacts. The framework covers a range of communication capabilities, includ
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
Realm is a mobile database: an alternative to SQLite & key-value stores
Parse Server is a backend-as-a-service solution and Node.js framework that provides a ready-to-use REST and GraphQL API for mobile and web applications. It functions as a core backend infrastructure for managing database schemas, user authentication, and API routing. The system distinguishes itself with a real-time data engine that pushes database updates to clients via WebSockets and a GraphQL server that automatically generates schemas based on application data models. It also features an adapter-based storage layer that abstracts interactions with various cloud and local backends. The pla
This project is an open-source software development kit and framework for implementing the Matter smart home standard. It provides a universal IPv6-based application layer and a cluster-based data model to ensure interoperability between diverse smart home devices and controllers. The system is distinguished by its multi-transport network abstraction, which maps Bluetooth LE, Thread, and Wi-Fi implementations to a common layer. It includes specialized tooling for secure device commissioning via QR codes and NFC, as well as a comprehensive over-the-air firmware update system for distributing s
This project is a reactive, offline-first NoSQL database engine designed for JavaScript applications. It provides a robust framework for managing application state by synchronizing data across browsers, mobile devices, and server-side runtimes. By treating local storage as the primary source of truth, it enables applications to remain functional without network connectivity, automatically reconciling changes with remote backends once a connection is restored. The database distinguishes itself through a modular architecture that supports cross-environment synchronization and high-performance d
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
Blynk is an embedded device framework and IoT cloud connectivity library designed to establish secure, bi-directional communication between microcontrollers and a remote management platform. It provides the core identity of an IoT device management tool, enabling the synchronization of device states, remote hardware control, and the mapping of hardware data to cloud-based interfaces. The project distinguishes itself through a virtual-pin system that decouples cloud communication from physical pins, allowing for hardware-independent data exchange. It also supports advanced architectural offloa
urql is a GraphQL client and data management tool used to execute GraphQL operations and synchronize data from remote servers within a software application. It functions as a mechanism for fetching, caching, and managing GraphQL data to maintain state across application views. The project features a pluggable middleware architecture and a normalized GraphQL cache. This allows for the insertion of custom logic into the request and response lifecycle to modify client behavior and the organization of responses by unique identifiers to ensure data consistency. The client provides capabilities fo
Materialize is a streaming SQL database that continuously ingests live data from sources such as Kafka, Redpanda, PostgreSQL, and MySQL, and incrementally maintains materialized views. It provides a PostgreSQL-compatible query engine that accepts standard SQL over the PostgreSQL wire protocol, enabling any existing SQL client or BI tool to query real-time data. The system also includes a Model Context Protocol (MCP) server that exposes live materialized view data to AI agents, providing fresh context without polling. Materialize distinguishes itself through its ability to offer configurable c
The inspector is a diagnostic and validation tool for the Model Context Protocol. It provides an interactive interface and a transport proxy to discover, inspect, and execute the tools, prompts, and resources provided by an MCP server. The project serves as a debugger and compliance tester to verify that server implementations adhere to the protocol specification and JSON-RPC standards. It allows for real-time monitoring of message exchanges and logs between clients and servers across various transport layers, such as standard input/output and Server-Sent Events. The tool covers a broad rang
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
myIPTV is a curated repository that aggregates live television stream URLs and organizes them into M3U-formatted playlist files. It operates as a static asset repository, delivering these playlists directly for use in external media players that support custom IPTV subscriptions. The project serves as a directory of high-definition live TV streams grouped by category, with each playlist available as a plain text file for maximum compatibility. What distinguishes myIPTV is its manual curation workflow and Git-hosted catalog. Playlists are hand-maintained by editors who verify stream availabili
Monica is a self-hosted personal relationship manager and CRM designed to track personal and professional connections. It functions as a contact management system and personal information manager, providing a centralized repository for detailed contact profiles, interaction logs, and relationship history. The system distinguishes itself by focusing on the nuances of personal connections, including gift cataloging, debt tracking, and personal journaling. It features a time-triggered notification system for scheduling contact reminders, such as birthdays and follow-up intervals. Broad capabili
This project is a comprehensive collection of Python programming education materials, including tutorials, exercises, and curated code samples. It serves as a learning curriculum and software engineering toolkit, utilizing Jupyter Notebooks to combine executable code with descriptive educational text. The repository provides practical implementation guides for building large language model applications, such as retrieval-augmented generation systems, stateful AI agents, and machine learning workflows. It distinguishes itself by offering a structured approach to agentic coding workflows, cover
This project is a structured learning curriculum and guide designed to transition a user from a beginner to an advanced level of Emacs mastery over the course of one year. It provides a step-by-step study plan, configuration guides, and a workflow manual to help users navigate the complexities of the editor. The guide emphasizes a specific operational model, focusing on the implementation of modal editing through Vim-style keybindings and the use of hierarchical leader-key mapping for command organization. It details the process of transforming the editor into a full development environment a
qqbot is a bot framework designed for building automated conversational agents and plugins using the SmartQQ client. It provides a conversational bot SDK for processing messages, managing group memberships, and executing event callbacks. The project is distinguished by its use of a headless browser automator to handle account logins and session management. It also includes an IRC chat bridge that functions as a gateway to forward conversations between a local IRC server and the messaging platform. The framework covers a wide range of capabilities, including dynamic plugin management, time-ba
GAM is a command-line tool for administering Google Workspace and Cloud Identity. It translates command-line arguments into structured API calls, enabling administrators to manage users, groups, organizational units, and domain settings across a Google Workspace environment. The tool handles authentication through OAuth2 flows, service accounts, and workload identity federation, and supports multi-tenant configurations for managing multiple domains or cloud projects from a single installation. GAM distinguishes itself through its batch processing and automation capabilities. It can process la
This project is a multi-format barcode library designed to encode and decode one-dimensional and two-dimensional barcodes across multiple programming languages. It functions as a cross-platform image processor that analyzes visual data to detect, locate, and extract information from patterns in diverse environments, while also providing a standard for mapping structured data into machine-readable formats. The library distinguishes itself through advanced image processing techniques that ensure reliability in real-world conditions. It employs pattern-matching detectors to identify geometric fi