Aerion - An Open Source Lightweight E-Mail Client

Maintained by: @hkdb

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❓ Why?

Windows has Outlook

Mac has Mail

Linux has..... - Thunderbird - Clunky and too much legacy structure - Geary - Crippled by Gnome Online Accounts and search is unreliable - Mailspring - Electron... - Evolution - ... 1999

All are not necessarily always light on resource consumption...

👁️‍🗨️ Summary

A standalone lightweight e-mail client inspired by Geary focused on achieving the following goals:

Resource Efficiency - Minimal CPU, RAM, and battery consumption
Modern UX - Clean, intuitive interface with dark mode support
Keyboard & Mouse Friendly - Full keyboard navigation with vim-style shortcuts
Independence - No dependency on Gnome Online Accounts or other system services
Search That Works - Basic search that actually finds your emails

🖥 OS Support

Although Linux is a first-class citizen here, it also works on:

MacOS
Windows

🪶 Features

Multiple Accounts
Providers: (🧪 = NOT YET TESTED)

- Generic IMAP/SMTP - GMail - Microsoft 365 / Outlook - Yahoo - Proton Mail (via Proton Bridge) - iCloud Mail - Mailfence - Murena - Fastmail 🧪 - Zoho Mail 🧪 - AOL Mail 🧪 - GMX Mail - Mail.com 🧪 - Mailbox.org

Unified Inbox (Color Code Accounts)
Conversation Threads
Basic Removal of Tracking Elements in Mail Content
WYSIWYG Detachable Composer (TipTap Editor)
WYSIWYG Signatures (TipTap Editor)
CardDav/Google/Microsoft Contact Sync for auto-complete
Basic Local and IMAP Search
Notification that brings focus to the e-mail when clicked
Auto-Sync when system wakes from suspend
Multiple color themes (More to come...)
PGP & S/MIME support
1st party extension system with the following shipped:

- Calendar (ALPHA) - Disabled by Default - Contacts (ALPHA) - Disabled by Default

Custom oAuth2 support for generic IMAP, SMTP, CarDAV, and CalDAV (Tested w/ Stalwart)
Keyboard Shortcuts

🚀 Installation

Official Installation Guide

📖 Documentation

Official Documentation

⚗️ Tech Stack

This application was built with Wails + Svelte.

Transparency Disclaimer: This project leaveraged Claude models heavily to implement.

Aerion is CASA Tier 2 Certified by Google's preferred authorized assessor: TAC Security

🗞 News & Announcments

2026-03-11 ~ Microsoft Verified
2026-04-16 ~ CASA Tier 2 Certified
2025-04-25 ~ Google Verified
2026-06-22 ~ Extension System + Contacts + Calendar (ALPHA)

🧑🏻‍💻 Roadmap

Confirmed future features:

Post quantum ready encryption
Add Mailfence and Startmail templates in add account flow for easier setup

Potential features in the future:

Customizable shortcut keys
Advance Search
AI Assisted Composition (Ollama)

🏷️ Changelog

CHANGELOG.md

💰 Sponsorship

3DF is sponsoring by way of dedicating its cloud infrastructure resources and the team's time to work on this. There's otherwise currently no sponsorship. If you like this project, please feel free to give us a star or buy us a coffee:

Google verification requires apps like Aerion to recertify for CASA Tier 2 every year which cost US$540 this year. This cost was sponsored one time by 3DF. Starting next year, we will have to depend on community or corporate sponsorship. If you want your "Buy Me a Coffee" donation to go specifically and only towards the annual CASA Tier 2 certification, in the "Say something nice..." field of the Buy Me A Coffee donation page, put, "For CASA" as the first line. You can leave the rest of the field empty or put whatever message you want to send us in the lines after.

🔨 Contributing

Please see CONTRIBUTING.md

🙏 Issue Contributors

Aerion is largely driven by community feedback. Big thanks to the following non-exhaustive list of contributors who submitted issues which led to meaningful improvements we all now enjoy. This project would not be the same without them!

_{keithvassallomt} _{21 closed}	_shahiljain _{7 closed}	_The-Nyla _{6 closed}	_lorduskordus _{4 closed}	_arnauda-gh _{4 closed}	_isorropisths _{4 closed}
_h-bernardo _{3 closed}	_slade991 _{3 closed}	_urdh _{2 closed}	_clintre _{2 closed}	_jeremy-niles _{2 closed}	_onny _{2 closed}
_Infiniti151 _{2 closed}	_SonGokuSSJ _{2 closed}	_pj398 _{2 closed}	_lawmanuk _{1 closed}	_{BurningTheSky} _{1 closed}	_az2oo1 _{1 closed}
_kevbrowngb _{1 closed}	_MMachado05 _{1 closed}	_CDrummond _{1 closed}	_tyderian1978 _{1 closed}	_Amjad50 _{1 closed}	_woolkingx _{1 closed}
_gpompeo _{1 closed}	_in4matix _{1 closed}	_etbe _{1 closed}	_kimusan _{1 closed}	_{extremeleadprogram} _{1 closed}	_Gerti1972 _{1 closed}
_alfureu _{1 closed}	_{Kartoffelbauer} _{1 closed}	_AdamHasma _{1 closed}	_{miguelmaiquez} _{1 closed}	_cvdmint _{1 closed}	_ilyonfly _{1 closed}
_Dragonsong3k _{1 closed}	_martink1337 _{1 closed}	_bjacobs39 _{1 closed}	_rdmrtn _{1 closed}	_ymilly _{1 closed}	_diederikh _{1 closed}
_CreateWebNZ _{1 closed}	_ai-mind _{1 closed}	_arodier _{1 closed}	_ajclarkin _{1 closed}	_idomusha _{1 closed}	_xJayMorex _{1 closed}
_hopeless65 _{1 closed}	_TheEmi _{1 closed}	_SantanuDatta _{1 closed}	_pascollin _{1 closed}	_DerKempter _{1 closed}	_initsuj _{1 closed}
_mff47025 _{1 closed}	_{justin-lavelle} _{1 closed}	_neodyme01 _{1 closed}	_rdannenbring _{1 closed}	_IvAzuara _{1 closed}	_robert0815 _{1 closed}
_srabette _{1 closed}	_frian92 _{1 closed}	_Arvid-ctrl _{1 closed}	_Olivetti _{1 closed}	_budfy _{1 closed}	_piresio _{1 closed}
_makzumi _{1 closed}	_PeterKDunn _{1 closed}	_mmzim05 _{1 closed}	_m-overlund _{1 closed}	_Albertmu2 _{1 closed}	_jakobkukla _{1 closed}
_HugoTheBoss _{1 closed}	_yuukiw _{1 closed}	_iCzora _{1 closed}	_xAptenodyte _{1 closed}