Outlook GitHub Repositories (2026) · Open Source Tools

MailCraft: an open-source, clean-room mail, calendar and contacts program in pure Rust, for Microsoft 365, Outlook.com and IMAP. Early alpha.

Leightweight windows calendar app

Sync your Outlook and Google calendars

Your work, already underway. A personal AI assistant for your job: mail, chats and tickets become tasks, the agents you already use (Claude Code, Codex, Gemini) do the work, and nothing goes out until you approve. Open source, runs on your machine.

Eppie — open protocol encrypted p2p email

📅 Calendar link generator for popular services

Microsoft 365 & Microsoft Graph Library for Python

DavMail POP/IMAP/SMTP/CalDAV/CardDAV/LDAP Exchange and Office 365 Gateway - Synced with main subversion repository at

Message Header Analyzer Add-in For Outlook

Pin a live Outlook calendar, inbox, tasks or any folder to your Windows desktop. Free since 2005, with 1.2M+ downloads.

STViewer is a viewer and search tool for email archives such as OST, PST, and mbox written in Rust. Runs on Windows, macOS and Linux

Converts email files (eml, msg) to pdf

Built-in Mail & Calendars app clone for Windows.