Awesome GitHub RepositoriesSMTP Server Implementations

Nodemailer is a comprehensive library for Node.js applications designed to handle the composition, signing, and transmission of email messages. It provides a robust framework for constructing MIME-compliant content, managing complex attachments, and routing messages through various delivery channels, including standard SMTP servers, local mail transfer agents, and cloud-based email services. The library distinguishes itself through a modular, plugin-based transport architecture that allows for custom delivery mechanisms and environment-specific configurations. It includes advanced features fo

Postal is an open-source email infrastructure and self-hosted delivery platform. It functions as an SMTP mail server and inbound email gateway, providing the tools necessary to send and receive email through a privately managed infrastructure. The system manages SMTP infrastructure for outgoing message delivery and provides capabilities for custom email receiving. It allows for the routing of incoming external emails to internal applications or websites for automated processing. The platform includes support for multi-tenant domain mapping, event-driven webhook notifications, and plugin-base

MailHog is an email testing tool that functions as a local SMTP server to capture outgoing messages during the development process. By intercepting SMTP traffic, it allows developers to verify email content, headers, and attachments without transmitting messages to actual external recipients. Captured data is stored in an in-memory buffer, ensuring that sensitive information remains accessible for inspection through a dedicated web-based dashboard. The platform distinguishes itself by incorporating network simulation capabilities, which allow for the injection of artificial delays or connecti

Healthchecks is a heartbeat monitoring service and cron job monitoring tool designed to track the execution and success of scheduled tasks and systemd timers. It functions as a dead man switch, alerting users when expected periodic signals from remote processes fail to arrive. The system accepts health signals via HTTP and SMTP, allowing it to track infrastructure heartbeats from sources ranging from CI/CD workflows to network routers. It distinguishes itself by supporting the capture of diagnostic data, including exit codes and execution logs, and by calculating the duration between start an

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

Mailcatcher is a local email development proxy and SMTP server mock designed to intercept outgoing emails during development. It acts as a network bridge that catches outbound mail on a specified port and displays it in a web-based inspector instead of delivering messages to real recipients. The tool provides a web-based email viewer for reviewing HTML, plain text, and raw source content, along with an interface for inspecting headers and downloading attachments. It utilizes a RESTful JSON API to serve captured mail as structured data to the browser interface. The system includes a TCP socke

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

Mox is a self-hosted email server that runs as a single compiled Go binary, handling the full lifecycle of sending and receiving email through SMTP, IMAP4rev2, and a built-in webmail application. It is designed to be operated without external dependencies or runtime plugins, with all mail services — including spam filtering, queue management, and web interfaces for administration and account management — contained in one executable. The server distinguishes itself through automated TLS certificate management via ACME, DNS-based autoconfiguration for email clients, and file-based configuration

Webmin is a web-based administration interface for Unix systems. It provides a centralized console for managing the full range of server administration tasks — users and groups, software packages, storage, network configuration, system services, and security — all through a browser. Its modular architecture allows separate modules to handle databases (MySQL, MariaDB, PostgreSQL), web servers (Apache), DNS (BIND), email (Sendmail, Dovecot), file sharing (Samba, NFS), and more, with a unified access control system that restricts what each administrator can see and do. What sets Webmin apart is

Laragon is a portable web server suite and WAMP stack manager that provides a self-contained local development environment. It enables the bootstrapping of web applications through the orchestration of web servers, databases, and language runtimes on a single machine. The project is distinguished by its registry-free portable mode, allowing the entire development stack to be moved between drives or computers without re-installation. It features automated virtual host mapping and SSL certificate generation for local domains, as well as a local tunneling gateway to expose projects via public UR

smtp4dev is a suite of tools featuring a mock SMTP server that intercepts outgoing email traffic and stores messages for inspection instead of delivering them to recipients. It includes a web-based viewer for inspecting email metadata, raw source code, and MIME structures, alongside a responsive email previewer that simulates how HTML emails appear across different viewport sizes and device layouts. The project provides a traffic analyzer to log protocol interactions and session data for debugging delivery failures. It also operates as a TLS SMTP server, supporting encrypted connections via T

该项目提供了一个容器化编排设置，旨在标准化 Web 应用的本地开发环境。通过利用声明式配置，它管理隔离的服务容器，以确保在不同开发者机器之间实现一致的应用行为和依赖管理。 该环境包括用于数据库持久化的集成实用程序，通过映射的存储卷确保数据在容器生命周期内保持完整。它还具有一个基于 Sidecar 的电子邮件拦截工具，可在本地仪表板中捕获并显示传出的消息，从而无需外部邮件服务器即可验证交付逻辑。 除了核心服务编排外，该项目通过提供容器化资产打包和编译工具来支持前端开发工作流。这些实用程序使开发者能够在隔离环境中执行构建过程并运行开发服务器，从而促进应用开发周期中的自动更新。