Open-source alternatives to Neomutt

Maddy is a modular mail server that assembles a complete email system by connecting small, single-purpose modules through a declarative configuration file. Rather than a monolithic stack, it lets operators compose message processing, storage, authentication, and security enforcement from interchangeable building blocks, with each module handling a specific function like receiving SMTP connections, verifying credentials, or applying policy checks. The server distinguishes itself through its flexible authentication and security architecture. It delegates user verification to external systems in

Libredesk is an omnichannel support management system designed to unify live chat and email communications into a single dashboard. It provides a comprehensive environment for managing customer interactions, agent roles, and team assignments to organize support workloads. The project distinguishes itself through AI customer support automation, which includes generating automated responses and refining message tones. It also supports the development and integration of custom chat widgets using WebSockets and JavaScript APIs. The system covers a broad set of capabilities, including customer re

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

Pop is a command-line email client and utility used to compose and deliver electronic messages directly from the terminal. It functions as a dispatch system that routes messages through SMTP servers or third-party API services. The tool includes a markdown composer that transforms markdown text into formatted HTML for email bodies. It manages sender identities and server credentials through a combination of persistent default configurations and environment variables. The system supports appending binary data from the local filesystem as attachments and provides a pipeline for automated email

This project is a cross-platform desktop email client built with web technologies. It serves as an extensible mail application that allows users to manage and organize email correspondence and can link to self-hosted synchronization engines to manage user data. The application is designed for extensibility through a plugin architecture and logic extension hooks, enabling the addition of custom features such as text translation, email templating, and external service integrations. It further distinguishes itself by providing a customizable interface that supports user-defined CSS styling and t

Thunderbird for Android is a mobile email application designed to synchronize and organize messages from multiple providers within a single unified interface. It functions as an email client that manages accounts through standard network protocols, allowing users to consolidate personal, professional, and educational inboxes into one central location. The application distinguishes itself through integrated support for end-to-end privacy, utilizing cryptographic standards to encrypt and decrypt email content directly on the device. It maintains a local relational database for message storage,

Mailspring is a cross-platform desktop email client designed to aggregate multiple accounts into a single, unified inbox. It utilizes standard protocols to synchronize messages and provides a centralized interface for managing professional correspondence across different email services. The application distinguishes itself through a suite of productivity tools that include automated message scheduling, follow-up reminders, and email engagement tracking to monitor recipient interactions. It also features contact enrichment to surface professional context and historical data, alongside built-in

SwiftMailer is an object-oriented PHP email delivery library used to compose and send email messages within applications. It represents emails as structured objects to manage headers, bodies, and attachments before they are serialized for transmission. The library utilizes a transport-based routing system to decouple message composition from delivery. This allows emails to be routed through different mechanisms, including authenticated SMTP connections to remote mail servers or local server binaries via Sendmail integration.

FairEmail is an open-source email client for Android that supports standard IMAP and SMTP protocols. It serves as a privacy-focused communication tool that manages multiple accounts through a unified inbox and provides PGP encryption and decryption for secure messaging. The application prioritizes data privacy by blocking tracking pixels and requiring manual confirmation before loading external images. It secures sensitive information through biometric authentication and personal identification numbers to restrict unauthorized access to the device. The client includes a suite of organization

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

Mailpit is an SMTP mail testing server and web-based email inbox designed to intercept and store outgoing emails for development and integration testing without delivering them to real recipients. It functions as an SMTP mocking tool and relay gateway, allowing users to capture mail traffic and view it through a browser interface. The project distinguishes itself by providing tools for SMTP server simulation, including the ability to inject failure codes to test application resilience. It also includes an email compatibility analyzer that validates HTML rendering, checks link integrity, and s

This project is a Telegram command line interface and MTProto client. It functions as a userbot framework, providing a terminal-based environment to interact with Telegram accounts without a graphical user interface. The system differentiates itself through extensibility, offering Python bindings and a Lua scripting engine to automate account tasks and respond to messages. It also serves as a JSON-based chat exporter, capable of extracting user metadata and conversation histories into structured files. The client covers core messaging capabilities, including text exchange, group chat managem

This project is a cross-platform messaging SDK and client development library used to build custom Telegram applications. It functions as a comprehensive framework that manages network encryption, local data storage, and API communication, providing a C-compatible JSON interface that allows integration with any programming language. The library distinguishes itself by providing a full database manager for encrypted local caching and synchronized state, alongside a dedicated bot framework for creating interactive bots with business account integration. It enables the implementation of speciali

Pyrogram is an asynchronous Python framework for interacting with the Telegram MTProto API. It serves as both a bot framework and a user client library, providing a concrete implementation of the MTProto protocol for secure communication with Telegram servers. The library distinguishes itself by providing a high-level wrapper layer that abstracts complex protocol methods into Python functions, while still allowing for the execution of raw API functions and low-level peer resolution. It supports multi-client concurrency, enabling the management of several user or bot identities within a single

This project is a cross-platform messaging client that implements a secure, real-time communication protocol. It provides a comprehensive development toolkit, including a database library and messaging SDK, which allows for the creation of custom messaging applications that maintain synchronized state across multiple devices. The core architecture relies on an asynchronous event-driven model to ensure responsive performance while managing persistent local database synchronization with server-side state. The client distinguishes itself through a robust end-to-end encryption layer that supports

Forge is a JavaScript cryptography library providing a comprehensive set of tools for symmetric and asymmetric encryption, hashing, and digital signatures. It includes a full Transport Layer Security implementation for establishing secure network connections and managing encrypted traffic. The project implements a wide array of public key infrastructure tools, including X.509 certificate management, the generation of certificate signing requests, and the validation of certificate chains. It provides a PKCS cryptographic toolkit for handling secure archives and signed messages, alongside suppo

Tink is a multi-language cryptography library and security toolkit providing secure APIs for data encryption and digital signatures. It functions as a data encryption library and digital signature framework designed to prevent common implementation errors across different platforms and operating systems. The project serves as a cryptographic keyset manager, utilizing JSON for the storage, rotation, and serialization of keys to maintain consistency across various programming languages. It ensures identical cryptographic behavior globally by mapping language-specific libraries to a unified set

EmDash is an open-source content management system built on Astro that combines a visual admin panel with a plugin-driven architecture and server-side rendering. It provides a complete content management system with structured content modeling, a rich text editor using Portable Text format, and a TypeScript API for type-safe content queries. The system supports authentication through passkeys, OAuth 2.1, and external providers, with role-based access control and fine-grained permission scopes. What distinguishes EmDash is its plugin development framework, which supports both native plugins ru

libhv is a high-performance C/C++ network library and event-driven I/O framework used to build TCP, UDP, SSL, HTTP, WebSocket, and MQTT clients and servers. It provides a non-blocking event loop for managing network sockets, timers, and system signals across multiple threads. The project is distinguished by its integrated support for specialized network roles, including a full HTTP web server with RESTful routing and middleware, an MQTT messaging client for IoT communication, and the ability to implement SOCKS5 and HTTP proxies. It also features a reliable UDP implementation to ensure ordered

ui-for-docker is a web dashboard and management interface for controlling and monitoring Docker containers. It provides a graphical alternative to the command line for visualizing the state of containerized workloads and administering Docker engines. The interface connects to the Docker daemon via local Unix sockets or remote TCP endpoints. It utilizes TLS certificates and keys to secure communication with remote engines and supports access restriction through HTTP basic authentication via a reverse proxy. The system operates as a stateless web frontend that translates user actions into requ

Anonaddy is an email forwarding gateway and alias manager designed to protect user identity. It functions as a mail server that routes messages from custom domains and aliases to verified destination addresses using programmable routing rules. The system provides an SMTP privacy proxy to mask the sender's real email address for outgoing messages and includes a PGP encryption tool to secure the body and headers of emails before they are forwarded. It supports custom domain email routing through DNS and MX record verification, allowing users to manage multiple identities to prevent ownership li

This project is a lightweight Node.js web server and command-line tool designed for hosting static assets and delivering local files over HTTP. It functions as a static site host that provides a minimal environment for serving HTML, CSS, and JavaScript files to web browsers. The server includes built-in support for TLS encryption to enable secure HTTPS access and allows for the configuration of cross-origin resource sharing headers. It also features basic authentication to restrict folder access via username and password verification. The system manages content delivery through browser cache

Inbox Zero is an AI-powered email automation platform and inbox organizer. It uses large language models to automatically categorize, label, and archive emails, while providing a conversational interface for managing workflows and drafting responses through natural language. The project distinguishes itself by integrating real-time calendar availability into its drafting process and generating AI-summarized meeting briefings. It supports a pluggable AI provider interface with model fallback chains, allowing it to connect to various cloud or local LLM providers. Users can also control their in

node-http-proxy is a Node.js HTTP proxy library used for forwarding requests to target servers. It functions as reverse proxy middleware capable of mapping incoming routes to target destinations and transforming request and response data streams. The library includes a WebSocket proxy gateway that upgrades standard HTTP connections into bidirectional streams between clients and backend servers. It also provides a response transformer for modifying bodies, location headers, and cookie domains. The project covers traffic routing management via rule-based translation tables and secure connectio

Infinity-For-Reddit is an open-source Android client and social content browser for Reddit. It functions as an API wrapper that allows users to browse and interact with Reddit communities on Android devices. The application covers Reddit account administration and community engagement, enabling users to vote on posts, save content, and submit text, images, or videos. It also provides tools for discussion management, allowing users to write, edit, and organize comment threads. The project includes capabilities for monitoring social activity through notifications and following users, as well a

SocketRocket is an Objective-C WebSocket client library designed to establish bidirectional real-time communication channels between an application and a server. It provides a networking layer for real-time data streaming, utilizing a heartbeat monitor to maintain the stability of active network streams. The library is built to operate across restricted networks by routing traffic through HTTP proxies. It secures data transmission using TLS encryption and SSL certificate pinning to prevent unauthorized interception of network traffic. Its underlying capabilities include low-level TCP socket

HP-Socket is a networking library for building scalable TCP, UDP, and HTTP servers and clients with event-driven I/O and SSL encryption. It provides a high-performance TCP server framework, an HTTP request handler that parses incoming requests and generates responses, and a UDP communication library for low-latency data transfer, all with optional SSL encryption for secure communication. The library is built on a completion-port-based I/O architecture that uses Windows I/O Completion Ports for scalable asynchronous socket operations. It features a connection-pooled agent architecture for mana