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

Ce projet fournit une configuration d'orchestration conteneurisée conçue pour standardiser les environnements de développement locaux pour les applications web. En utilisant une configuration déclarative, il gère des conteneurs de services isolés pour garantir un comportement d'application cohérent et une gestion des dépendances sur différentes machines de développeurs. L'environnement inclut des utilitaires intégrés pour la persistance des bases de données, garantissant que les données restent intactes à travers les cycles de vie des conteneurs via des volumes de stockage mappés. Il dispose également d'un outil d'interception d'e-mails basé sur un sidecar qui capture et affiche les messages sortants dans un tableau de bord local, permettant la vérification de la logique de livraison sans avoir besoin de serveurs de messagerie externes. Au-delà de l'orchestration de services de base, le projet prend en charge les workflows de développement frontend en fournissant des outils de bundling et de compilation d'assets conteneurisés. Ces utilitaires permettent aux développeurs d'exécuter des processus de build et d'exécuter des serveurs de développement au sein d'un environnement isolé, facilitant les mises à jour automatiques pendant le cycle de développement de l'application.