fastapi-mail is a lightweight async Python library for sending emails from FastAPI/Starlette applications. It provides a clean, Pydantic-driven configuration model (ConnectionConfig), a message builder (MessageSchema) supporting HTML, plain text, Jinja2 templates, file attachments, CC/BCC/reply-to, and custom SMTP headers. The core FastMail class handles async SMTP delivery via aiosmtplib, with optional Redis-backed email validation utilities (DefaultChecker) and a WhoIsXmlApi wrapper. The architecture is simple and single-purpose: a library to be imported into FastAPI projects. It has comprehensive test coverage (22+ async tests) and modern async patterns throughout. The codebase is well-maintained with CI/CD, linting, and documentation. While the library does not exhibit groundbreaking innovation, it is a solid, production-ready solution for email sending in async Python web applications.
python-o365 is a mature Python library that provides a comprehensive, object-oriented wrapper around the Microsoft Graph API. It enables developers to programmatically access and manage Microsoft 365 services including Outlook email and calendar, OneDrive and SharePoint files, Teams chats and presence, Planner tasks, directory users and groups, and more. The library abstracts OAuth2 authentication (supporting authorization code, public client, and client credentials flows) and handles token refresh, pagination, and API versioning internally. It is designed as a client-side SDK, not a server application, and can be embedded into scripts, web applications (e.g., Flask), or automation workflows.
Sup is a console-based email client written in Ruby, designed for heavy email users who prefer a keyboard-driven, terminal interface. It provides a Gmail-like workflow with thread-centric conversation view, labeling (tags), archiving, muting, and full-text search powered by Xapian. The application supports multiple local mail sources (mbox and Maildir), multiple accounts, and can be extended via Ruby hooks. It runs as a full-screen ncurses application with a buffer-based window manager, offering modes for inbox, search results, compose, reply, forward, and more. Architecturally, Sup follows a modular pattern with manager classes (PollManager, UpdateManager, UndoManager, DraftManager, etc.) that encapsulate state and behavior. The UI is built on a Mode hierarchy with a shared keymap DSL, allowing consistent keyboard navigation across different views. The core data flow involves polling mail sources, parsing messages with RMail, threading them using a JWZ-inspired algorithm, and indexing them into a Xapian database for fast search. Labels and state are persisted in YAML files and the Xapian index. Key entry points include the main `bin/sup` TUI, `bin/sup-sync` for index synchronization, `bin/sup-add` for adding sources, and various utility scripts. External dependencies include ncursesw, RMail, Xapian, GPGME, and Chronic for date parsing. The project is in maintenance mode, focusing on stability and bug fixes rather than new features, but remains actively maintained with CI across many Ruby versions.
iKy (I Know You) is a modular OSINT (Open Source Intelligence) aggregation platform built with FastAPI, Celery, Redis, and an Angular frontend. The system ingests a username or email and concurrently executes 26+ parallel tasks across social media, data breaches, search engines, and dark web sources, returning a structured JSON contract (module, param, validation, raw, graphic, profile, timeline, tasks) consumed by a visual graph/timeline UI. Key architectural patterns include a dynamic module registry that maps route names to Celery task paths, a decorator-based task wrapper (@iky_task) that centralizes dev-mode golden-file bypass, error classification, and performance logging, and a pluggable search provider orchestration layer. The codebase demonstrates a strong separation of concerns between API routing, task execution, and data enrichment, but suffers from fragile scraping logic (LinkedIn RSC parsing, TikTok SSR regex), heavy reliance on browser session cookies, and several deprecated external APIs (Twitter v1.1, FullContact). The project is actively maintained with an extensive test suite (~4K lines) and Docker Compose deployment, though many tests are heavily mocked and may not detect real API drift.
This is a Craft CMS plugin that provides contact form functionality for websites. It allows users to create and submit contact forms with fields for name, email, subject, and message, with support for file attachments. The plugin processes form submissions, validates input, constructs email messages (both plain text and HTML), and sends them via Craft's mailer system. It follows a standard MVC architecture where controllers handle HTTP requests, models represent data (submission and settings), and services (Mailer) handle the core email processing logic. The plugin is extensible through events (beforeSend, afterSend) that allow other plugins to modify behavior. Key features include AJAX form submission support, configurable email templates, attachment handling with file type validation, and multi-language support.
EmailThing is a self-hosted email service providing web (PWA), CLI, and API interfaces for sending and receiving emails with custom domains. The system consists of a Bun-based backend API using PostgreSQL with Drizzle ORM, a React/Next.js PWA with Dexie IndexedDB for offline capabilities, and a CLI tool for management. It handles email storage via S3, authentication with JWT/sessions and passkeys, rate limiting with Redis, and integrates with external email services for sending while using Cloudflare Workers for reception. The architecture follows a monorepo pattern with clear separation: apps/api (backend server), apps/pwa (frontend interface), apps/cli (terminal tool), and shared packages for database, constants, and SDK. Key features include multi-user mailbox management, aliases, custom domain support, team collaboration, end-to-end encryption for sensitive data, and real-time synchronization between client and server. The system emphasizes user control over email infrastructure while providing modern web application experiences.
This is a lightweight SMTP server written in Go, designed to receive large volumes of email, parse MIME content, and store messages in MongoDB. It includes a web interface for viewing messages, managing greylisting, and real-time notifications via WebSockets (using the embedded Incus library). The server implements core SMTP commands (HELO/EHLO, MAIL, RCPT, DATA, AUTH, STARTTLS, XCLIENT) and supports TLS, greylisting, and spam filtering via regex. The architecture is monolithic: a single binary runs both the SMTP listener and an HTTP server for the web UI. The codebase is functional but shows signs of age: it uses deprecated dependencies (gopkg.in/mgo.v2, github.com/robfig/config, github.com/gosexy/redis), lacks a go.mod file, and has no automated tests. The SMTP protocol handling is reasonably robust, and the MIME parsing is non-trivial, but the overall project would benefit from modernization and testing.
Nylas Mail is an open-source email client built with Electron, React, and a Flux-like architecture. It consists of a desktop application for managing email accounts, composing messages, and organizing threads, backed by Node.js microservices (cloud-api, cloud-core, cloud-workers) for synchronization and extended functionality. The codebase features a plugin system for extensibility, a UI kit (nylas-component-kit), and reusable components like FixedPopover and TokenizingTextField. However, the repository is explicitly archived (since 2017) and depends on outdated technologies (Node 6), indicating significant technical drift.
This is a minimal example repository demonstrating how to integrate Resend email service with Next.js App Router. It contains a single API route that sends an email using a React email template. The repository is deprecated and has been consolidated into a monorepo. It serves as a basic reference but offers no reusable components or advanced patterns.