C# Email Libraries

MailKit is a cross-platform .NET email protocol library used to implement IMAP, POP3, and SMTP functionality. It provides specialized client libraries for managing remote mailboxes, retrieving and downloading messages, and composing and transmitting emails to remote servers. The library supports secure identity verification through SASL authentication and OAuth 2.0 token-based flows. It includes capabilities for routing traffic through proxy gateways and decrypting PGP-encrypted content embedded within email bodies. The project covers a broad range of email operations, including folder manag

A .NET MIME creation and parser library with support for S/MIME, PGP, DKIM, TNEF and Unix mbox spools.

Gophish is an open-source phishing toolkit and simulation framework designed to test organizational security awareness and evaluate vulnerability to social engineering attacks. It provides a core engine for sending deceptive emails to targets and tracking their interactions to identify gaps in security training. The platform functions as a comprehensive campaign manager for deploying lures and monitoring email delivery and click-through rates. It allows for the design and execution of simulated email threats to track how targets interact with malicious-looking content or provide credentials i

NeoMutt is a terminal-based electronic mail management system that provides a text-based user interface for reading and composing emails. It functions as a mail manager and client supporting IMAP, POP3, and SMTP protocols, as well as NNTP for newsgroup access. The project distinguishes itself through integrated support for PGP and S/MIME encryption, providing tools for signing and encrypting messages and managing cryptographic keys. It supports modern authentication via OAuth2 and offers specialized MIME-aware reading capabilities for decoding multipart messages and visualizing MIME structure

Roundcube is an open-source, self-hosted webmail client designed for reading, composing, and organizing emails stored on remote servers using IMAP and SMTP protocols. It provides a browser-based interface that allows users to manage their mailboxes and sender identities through a secure communication platform. The platform is distinguished by its modular architecture, featuring a plugin-based extension system for adding new functional modules and a skin-based theme layer for customizing the visual appearance and responsive layouts. It further supports embedding its interface into external clo

Flurl is a .NET fluent URL builder and HTTP client wrapper designed for constructing complex web addresses and sending requests with a chainable interface. It functions as a URL manipulation library and an HTTP mocking framework to facilitate network interaction and testing. The project distinguishes itself through a fluent interface that allows for the incremental construction of paths, query parameters, and fragments. It provides a dedicated mocking system to intercept outgoing network traffic and return predefined responses, enabling isolated unit testing without a live server. Its broade

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

Curl is a command-line tool and portable library for transferring data across a wide range of network protocols. It functions as a unified engine that abstracts diverse communication standards, allowing users and developers to move files and information between servers using a consistent interface. The project provides both a versatile command-line client for terminal-based automation and a stable programmatic interface for integrating complex network operations into applications. The system is distinguished by its protocol-agnostic core and its ability to manage both synchronous and asynchro

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