Open-source alternatives to Keybase Client

This project is an Android password manager application that provides an end-to-end encrypted vault for storing and synchronizing login credentials, secure notes, and identities. It functions as a secure storage system using zero-knowledge encryption to ensure that only the user can decrypt their stored data. The application integrates directly with the Android system to provide an autofill service that populates usernames and passwords into mobile apps and browser login fields. It also serves as a passkey management wallet for FIDO2 cryptographic passkeys and a time-based one-time password a

OpenKeychain is a mobile OpenPGP key manager and identity provider used for storing, importing, and organizing encryption keys and digital certificates. It serves as an end-to-end encryption client and digital signature tool for encrypting and decrypting text and files. The application functions as a central vault that provides encryption and decryption services to third-party apps, such as email clients and password managers. It enables secure public key exchange through online directory retrieval and QR code scanning. The project covers cryptographic identity verification, including the ab

Dootask is an open-source project management tool and self-hosted task orchestrator designed for task distribution, project tracking, and document management. It functions as a collaborative platform that integrates team communication and workflow organization within a single workspace. The platform includes a collaborative document suite for creating shared documents, mind maps, and flowcharts. It also operates as an encrypted team communication platform, utilizing asymmetric encryption to secure internal conversations and data exchange. The system covers broader capabilities in identity ma

Ockam is an end-to-end encryption framework and distributed identity provider designed to establish secure communication between applications and devices. It provides a secure network overlay that utilizes cryptographic identities and attribute-based access control to implement zero trust network access. The project distinguishes itself through metadata-driven multi-hop routing and a pluggable transport layer, allowing encrypted traffic to move across diverse network topologies without requiring virtual IP overlays. It specifically enables secure tunneling for legacy applications by wrapping

gocryptfs is a FUSE-based encrypted filesystem that transparently encrypts and decrypts file contents and filenames on disk. It uses block-level authenticated encryption with AES-GCM or AES-SIV-512, binding each block to its file header and offset for integrity, while obfuscating filenames with EME or AES-SIV wide-block ciphers using per-directory initialization vectors. The system derives all encryption keys and initialization vectors deterministically from a master key using HKDF and SHA256, enabling reproducible ciphertext for reliable backup and synchronization workflows. The project dist

SSHFS is a network filesystem client that maps remote server directories to local mount points. It functions as a userspace implementation of a filesystem, allowing users to access and manage remote files as if they were on a local disk using the SFTP protocol over SSH. The tool distinguishes itself by offering multiple transport options, including encrypted SSH tunnels for security and direct TCP socket connections to bypass encryption for higher throughput. It also supports connectivity via virtual sockets to access directories hosted inside virtual machines. The system includes capabiliti

Alist is a unified cloud storage gateway that aggregates disparate remote storage providers into a single, navigable virtual file system. By acting as a remote file system proxy, it decouples file operations from specific provider implementations, allowing users to browse, download, and manage files across heterogeneous backends through a standardized interface. The platform utilizes a driver-based storage abstraction that translates generic file system operations into provider-specific API calls. This architecture supports a wide range of cloud storage services, S3-compatible object storage,

Cyberduck is a multi-protocol file transfer client and cross-platform file manager for Mac and Windows. It functions as a cloud storage manager and remote storage mounter, allowing users to upload, organize, and synchronize data between local drives and remote endpoints. The application provides a unified interface for managing files across FTP, SFTP, WebDAV, S3, and other cloud storage protocols, including Amazon S3, Backblaze B2, Microsoft Azure, and OneDrive. It distinguishes itself with a client-side encryption vault that encrypts files and folders locally before they are transmitted to r

SSHFS-Win is a Windows implementation of SSHFS that mounts remote directories over SSH as local Windows drives, enabling seamless file access as if they were local network drives. It provides both command-line and graphical interfaces for creating, managing, and disconnecting SSHFS mounts, supporting password or SSH key authentication with optional credential storage in the Windows Credential Manager. The project extends beyond basic SSH mounting to support a wide range of remote file access scenarios, including mounting cloud storage services like Azure Blob or Amazon S3, distributed POSIX f

WinFSP is a framework for implementing custom file systems on Windows. It enables the creation of user-mode file systems that appear as standard disk drives or network shares to the operating system, allowing developers to implement file system logic in user space via a proxy architecture that avoids the need for custom kernel code. A primary differentiator is its FUSE compatibility layer, which maps POSIX-based file system calls to native Windows requests. This allows existing file systems written for the FUSE API to be ported to Windows and Cygwin environments. The project covers a wide ra

Hypercore is a distributed append-only logging system designed for maintaining cryptographically signed data streams that are replicated and verified across a network of peers. It provides verifiable data storage using a Merkle tree structure to ensure the integrity and authenticity of information through cryptographic proofs. The project is distinguished by its support for sparse data replication, which allows peers to download only the specific ranges or blocks of a log required for their current needs to reduce bandwidth. It also implements encrypted peer-to-peer messaging and the ability

ServiceStack is a high-performance .NET web framework designed for building type-safe APIs using strongly-typed request and response objects. It functions as a message-based API engine that decouples business logic from the transport layer, allowing services to be exposed via multiple protocols including HTTP, gRPC, and various message queue providers. The framework is distinguished by its type-safe API generator, which produces native client SDKs and data transfer objects from service metadata across multiple languages. It also includes a distributed service gateway for microservices orchest

This project serves as a comprehensive technical reference and educational platform for the Ethereum ecosystem. It provides a deep dive into the fundamental architecture of decentralized ledger systems, covering the core mechanisms that enable trustless state transitions, cryptographic security, and network consensus. The documentation distinguishes itself by bridging high-level conceptual frameworks with practical implementation details. It details the lifecycle of smart contract development, from source code compilation and bytecode analysis to deployment and interaction patterns. Furthermo

NSwag is an OpenAPI toolchain for .NET that provides a suite of generators for converting OpenAPI specifications and JSON schemas into clients, server stubs, and structured documentation. It enables the creation of type-safe client libraries and data transfer objects, as well as the generation of OpenAPI specifications by analyzing .NET controllers. The project supports contract-first API development by generating server controller stubs from specifications and offers dedicated TypeScript API integration to ensure type safety in frontend applications. It also provides tools for hosting intera

Centrifugo is a self-hosted real-time messaging server that provides infrastructure for scalable notifications, a publish-subscribe message broker, and a language-agnostic WebSocket gateway. It allows for the delivery of instant messages and data streams to concurrent users via WebSockets and Server-Sent Events. The system functions as a communication layer that separates network transport from backend business logic. It supports distributed messaging clusters using Redis for coordination of presence and message delivery across multiple server nodes. The project covers channel subscription m

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This project is a cross-platform implementation of the WebRTC standard, providing a comprehensive library for building real-time audio, video, and data communication applications. It functions as a peer-to-peer networking framework and media processing engine, enabling direct, low-latency connections between devices without relying on central servers. By strictly adhering to official protocol specifications, the library ensures interoperability with browsers and other native communication software across mobile, desktop, and server environments. The engine distinguishes itself through a modul

This project is a self-hosted, cross-platform instant messaging platform featuring a Go backend and a protobuf-based messaging server. It provides a unified communication suite with native clients for iOS, Android, and web, utilizing gRPC and Protocol Buffers for efficient data exchange. The system is distinguished by an extensible chatbot framework that allows for the integration of automated bots and plugins via standardized service interfaces. It supports high-availability clustering with sharded load distribution and a pluggable database backend to ensure reliability and flexible data per

This repository is a comprehensive collection of reference implementations and sample libraries for the Universal Windows Platform. It provides practical examples of how to use Windows Runtime APIs to build cross-device applications, including detailed guidance on XAML-based declarative user interfaces and DirectX-integrated rendering. The project distinguishes itself by providing a wide array of hardware integration suites, covering low-level communication with USB, Serial, I2C, SPI, and GPIO peripherals. It includes specialized implementations for mixed reality holographic rendering, advanc

yapi is an API management platform designed to coordinate the development of RESTful APIs between frontend, backend, and quality assurance teams. It functions as a centralized system for documenting interface specifications, simulating server responses, and validating requests through a built-in testing client. The platform features an API code generator that transforms interface specifications into typed request functions and data models across multiple programming languages. It also includes a mock server capable of generating synthetic responses using schema-based generators and rule-based

The AWS Cloud Development Kit is an infrastructure-as-code framework that enables developers to define and provision cloud resources using familiar programming languages. By utilizing construct-based synthesis, it translates high-level, object-oriented code into declarative templates, allowing for the automated management of complex cloud environments through a centralized, code-driven control plane. The framework distinguishes itself through its ability to model infrastructure as a dependency-aware resource graph, ensuring that components are provisioned and updated in the correct order. It

Signal-iOS is an encrypted messaging client that provides secure communication for voice calls, media, and text. It functions as a complete implementation of the Signal Protocol, utilizing end-to-end encryption to ensure that only intended recipients can access transmitted data. The application distinguishes itself through the integration of advanced cryptographic standards, including the use of elliptic curve cryptography for identity verification and digital signature validation. It employs a double ratchet key exchange mechanism to rotate encryption keys for every individual message, ensur

This project is a decentralized, privacy-focused messaging platform designed to eliminate reliance on central servers and persistent user identifiers. By utilizing a metadata-minimizing protocol, it ensures that all communication remains end-to-end encrypted and that user identities are stored exclusively on the local device. The architecture relies on relay-based message routing and identity-free network addressing to maintain data sovereignty and prevent the correlation of user activity. What distinguishes this platform is its commitment to traffic isolation and anonymity. Each conversation

libsignal is a cryptographic library that implements the Signal Protocol, providing the core primitives for end-to-end encrypted messaging with forward secrecy and deniable authentication. It includes the Double Ratchet algorithm for iteratively deriving fresh encryption keys per message, and the X3DH key agreement protocol for establishing shared secrets between parties asynchronously. A session state machine maintains cryptographic state across message exchanges, supporting recovery and out-of-order delivery. The library extends beyond basic messaging encryption with capabilities such as ze

Toxcore is a peer-to-peer networking library that implements a decentralized communication protocol for secure messaging and media calls without the use of central servers. It provides a core engine for establishing direct encrypted connections between devices using a public-key identity system where unique identifiers serve as both addresses and authentication keys. The project features a decentralized network architecture that utilizes a distributed hash table for peer discovery and Kademlia-based routing to locate participants. To maintain connectivity across restrictive network environmen

Element Android is a decentralized instant messaging application built on the Matrix protocol. It enables users to exchange messages and collaborate across different servers without relying on a single central provider. The application focuses on data privacy and security through end-to-end encrypted messaging, ensuring that private messages and files are only readable by the intended recipients. It supports secure team collaboration via encrypted channels and provides cross-platform chat integration.

Converse.js is an embeddable, self-hosted XMPP chat client that runs entirely in the browser. It communicates with XMPP servers using standard XML stanzas over WebSocket or BOSH transports, and provides end-to-end encryption through the OMEMO protocol with double ratchet algorithm and X3DH key exchange. The client is built on a plugin-based architecture that allows extending core functionality at runtime without modifying the client itself, and uses a DOM-based rendering approach with an event-driven message bus for internal coordination. The client manages message history through XEP-0313 Me