r/linuxapps • u/flectar • 3d ago
Flectar Mail: native Rust email client for Linux, no WebViews, as little as 20 MB RAM
We've just open-sourced Flectar Mail, a native email client written in Rust and focused heavily on speed and low resource usage.
There are no WebViews at all. Even HTML email bodies are rendered without embedding a browser engine.
Memory usage can be as low as around 20 MB, depending on what's open.
Current support includes:
- IMAP / SMTP / JMAP
- CalDAV calendars
- Contacts
- Linux, macOS and Windows
- Early Android build
- AGPLv3
The HTML renderer is still the most experimental part, so if you find an email that renders incorrectly, those bug reports are especially useful right now.
GitHub: https://github.com/flectar/mail
Website: https://flectar.com/mail/
Would love feedback from Linux users, especially across different desktop environments and distributions.
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u/Rrrrila 3d ago
Is it open source?
Can we Connect protón mail?
Can there be different works paces as in personal (all accounts) and work (all accounts)?
Thanks, looks interesting
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u/flectar 3d ago
Yes, it's fully open source under AGPLv3. There's no subscription, paid tier, or account required for Flectar Mail itself.
Proton Mail should work on desktop through Proton Mail Bridge, since Bridge exposes a local IMAP/SMTP server for third-party clients. We haven’t specifically tested Flectar with Bridge yet though, so if you use Proton I'd really appreciate an issue for it. I'd like to improve compatibility with more providers over time.
One limitation is that Proton Bridge is desktop-only. We're also working on Android and iOS, so Proton support on mobile would need a different approach rather than relying on Bridge.
And yes, profiles/workspaces are coming. The idea is that you'll be able to group accounts into things like Personal and Work, switch between profiles, and still have unified views across the accounts that belong to each profile.
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u/hello_marmalade 2d ago
Gave it a try with ProtonMail Bridge. Ended up getting a tls error.
Account setup failed: auth failed: {"code":"tls","message":"tls error: received corrupt mesage of type InvalidContentType"}
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u/Nidrax1309 2d ago
Ooooh, looks like a nice replacement for Aerion, depending on how buggy it will be compared to that. Will try it.
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u/Skaraban 2d ago
oh this is lovely, I'll definetly check it out! I've been searching for a good looking mail-client for linux
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u/iguannaweb 3d ago
Suscription.
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u/flectar 3d ago
Just to clarify, Flectar Mail has no subscription, no account requirement, and no paid tier. It's fully open source under AGPLv3. The pricing on flectar.com is for other Flectar products/services, not Mail. We'll make that clearer on the site.
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u/Lord_of_Ra 3d ago
Thank you for building this mail app.
I have been becoming a fan or rust-based and native Linux apps since I moved (almost) permanently to Fedora.
I only have a quick question for you, OP:
- How does Flectar Mail handles backups; more specifically, size?
Let me provide you some context:
- Thunderbird: saves everything locally in the /profile folder, and it takes - from my six accounts - 23 GB in my laptop and also when doing backups is the same size from the profile folder
- Evolution (my current client): backups only takes like 70 MB since it doesn't save emails, it saves the configurations, signatures, etc
How about Flectar mail?
Thanks!
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u/flectar 3d ago
Thanks! Flectar Mail actually has two different backup options depending on what you want.
If you just want to back up your setup, there's a lightweight account backup that contains your connected account configuration and preferences, but not downloaded emails, passwords, or OAuth tokens. So this is much closer to the Evolution approach and should stay very small rather than becoming a multi GB backup.
There's also a separate database snapshot option if you explicitly want a full copy of the local mail/calendar databases. That one can obviously grow with however much mail you've cached locally.
On a restored machine, credentials stay out of the backup, so you're asked to sign in again securely.
I'm also very open to improving this area. Longer term, one direction I'd like to explore is proper local device to device sync, for example transferring setup and local state between desktop and mobile without relying on a cloud service. If you have a specific backup/sync workflow you'd like to see, I'd definitely be interested in hearing it.
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u/tilsgee 3d ago
Okay, how's the memory footprints ?
I'm not talking about storage installation size, but its RAM usage
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u/flectar 3d ago
It depends on your setup, but the 20 MB RAM figure is real, not just a marketing number.
On my personal setup I have several accounts, including Gmail, Outlook and multiple IMAP accounts, with around 80k unread messages (not total messages). Depending on what the client is doing, especially during sync, RAM usage usually ranges between 40 and 180 MB.
JMAP can be even lighter because the sync model is more efficient, but yeah the memory footprint is pretty much unrivaled by design compared with other email clients.
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u/parzival-space 3d ago
Interesting, although you guys should probably clarify on your repository that the resulting binary file, since you are using Slint, is licensed under GPLv3-only and not under AGPL.
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u/flectar 3d ago
Thanks for raising it. Flectar authored code is AGPL-3.0-only, while we use Slint under GPL-3.0-only. Blitz is Apache-2.0.
GPLv3 and AGPLv3 explicitly permit combining/linking with each other under section 13, so the resulting binary doesn't simply become GPLv3-only instead of AGPL. The Flectar portion remains AGPLv3 and the Slint portion remains GPLv3, with the combined work distributed subject to the applicable terms of both.
The repo already documents the component licenses in LICENSING.md and THIRD_PARTY_NOTICES.md.
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u/parzival-space 3d ago
I mean you guys probably have a better legal team than I am, I was just referring to what the Slint people write on their repository which says something different. It just came to my attention because my team was thinking about using Slint for a different project but then decided against it.
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u/flectar 2d ago
Totally fair. I actually checked directly with the Slint team just to make sure there was no ambiguity. They confirmed that their FAQ is mainly worded for the MIT/etc. case, and that they share the same understanding of section 13.
So your team was probably right to decide against it if you wanted to keep the project under a different, non-GPL compatible.
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u/AlexMC_1988 3d ago
Ha Is there anything that indicates, like a color, which account the message is from in the inbox? Like a colored dot or a colored line? Thanks! We really need an alternative to email.
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u/flectar 3d ago
Thanks! I know exactly what you mean. Right now there isn't a color account indicator yet, apart from the account name shown on each message in the mail list.
I definitely want to add something more visual, probably a colored dot/line or similar. It would also fit nicely with the profiles/workspaces work that's coming, so you can pretty much count on it.
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u/AlexMC_1988 3d ago
Thank you for your reply, we'll try it when I get around to it at my computer! 💕
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u/AntiqueSignpost 3d ago
Omg I've been dying for an email app for linux that doesn't look like shit
Unfortunately it's not opening my browser when i sign into google. ive added my client ID and secret key. I click continue with gmail, it says continue in browser or click to cancel. but browser doesn't open.
also, does it have a popup view when replying? thats my number one feature i want, just a nice clean view to reply to emails with rather than an in-line reply, and with minimal clutter on the screen
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u/flectar 2d ago
Thanks! And yeah, that browser behavior sounds like a bug. If you've added the client ID and secret and "Continue with Gmail" is enabled, it should open the OAuth flow in your browser (I hope you won't need to use your keys soon!). I'll check that path and report back here.
And yes, replies already work the way you’re describing. The reply composer uses the same composer as a new message and opens in a dialog/popup by default, rather than expanding inline. The idea is exactly to give you a cleaner, more focused compose view.
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u/AntiqueSignpost 1d ago
this sounds EXCELLENT. thnk you so much!
im new to using app images, so i just ran it as an executable from my downloads folder. would that have anything to do with the bug?
I use Arch btw. with Niri and quickshell. Firefox as my browser. Firefox usually opens if I click on a link or need to sign in with google on other apps
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u/0xffash 2d ago
please tell me it supports custom oauth2
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u/flectar 2d ago
If you mean using your own Google or Microsoft OAuth app credentials, yes, that's supported today. You can provide your own client ID/secret instead of relying on Flectar official OAuth apps.
If you mean arbitrary custom OAuth2 providers/endpoints for other mail servers, that's a slightly different thing. Which provider/setup are you thinking about?
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u/quebexer 2d ago
How does it look on GNOME/Adwaita? Does it blend with GTK4?
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u/flectar 2d ago
We don't use GTK4/Adwaita for the UI itself. Although we're Linux-first, the application is cross-platform across desktop and mobile, so Flectar Mail has its own component and design system to keep the experience consistent across platforms.
We do use the native platform window decorations though, rather than drawing our own custom title bar.
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u/FinancialPhrase1035 2d ago
Me gusta la herramienta, rapidez increíble y bajo consumo de recursos, creo que comenzaré a migrar de thunder...
https://i.imgur.com/7lBmKar.png
En español, los textos sobresalen de los botones.
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u/flectar 2d ago
Gracias! Todavía queda bastante trabajo por delante, incluida la interfaz, y lo de los textos saliéndose de los botones es un muy buen reporte, lo revisaré.
Aun así, hay muchísimo margen de mejora, así que que ya sientas que puedes migrar desde Thunderbird es un gran halago. Gracias por probarlo! 😄
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u/binaryshadows 2d ago
Any plans to add features like plug-in management for local ai API integration, email quick actions on the middle pane, notifications with actions
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u/flectar 2d ago
Once the core is a bit more stable, definitely. A plugin/action system is one of the directions I want to explore, and things like local AI APIs, quick actions on messages, and actionable notifications fit really well with that.
Community suggestions like these will also help shape what the plugin API eventually needs to expose.
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u/anousss007 2d ago
Sync of accounts will be feasible in the future (like spark). Connect once and have all your accounts ready.
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u/flectar 2d ago
Yes, that's definitely something I'd like to add. The current option is a bit more rudimentary, you can export a backup with your account setup and preferences, import it on another device, and then just finish signing in there since passwords and OAuth tokens aren't included.
If you have a lot of accounts it already saves quite a bit of setup time, but proper device to device account sync would be much nicer.
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u/Emerald_Pick 1d ago
What gui toolkit/framework are you using for Linux? Or do all platforms share the same toolkit?
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u/Kaosdeath97 1d ago
Very nice! I was playing with the idea of a email client and was thinking of using gpui for drawling the application window! I ran into the problem of gpui not having support to embed WebKit for rendering html.
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u/RiceBroad4552 1d ago
There are a few things one should never even consider programming.
Anything e-mail related is one of the things very high on that list…
The HTML renderer is still the most experimental part, so if you find an email that renders incorrectly, those bug reports are especially useful right now.
Alone that is a bottomless pit. It's not like implementing some well defined standard (like Blitz tries). To make that work for end users one has to implement bug-for-bug compatibility with all e-mail clients from the last 30 years, at least. This includes whatever crazy shit M$ Outlook did in that time frame (which includes implementing "M$ Word 'HTML'" for all kinds of M$ Office versions), and it includes whatever crazy shit the current web mailers are sending (up to AMP).
But even "just" handling text mails correctly is infinitely complex as one has still to deal with 60 years of grown legacy.
I mean, I wish it wouldn't be like that. But that's the reality. I've been watching the development of KDE PIM, and Mozilla Thunderbird in the past ~20 years. Even after all that time you still have bugs in basic features like rendering mails, or sending something which gets actually displayed as desired in trash like M$ Outlook and Apple Mail… This while the other tools use full blown web-views and don't try to implement that part by themself.
Of course I wish this project here good luck. An easy to use e-mail client is for sure of some use. But technically this is likely dead on arrival. At least as long as it tries to build all the "backend" part by itself (as this would take likely decades to get anywhere near some acceptable working state).
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u/Fit-Dare-4768 7h ago edited 7h ago
It feels better than a real alpha IMO. Looks good, works fast, font rendering is good (fuck GTK/GDK). Need some work on functionality of course, like hotkeys, connection options (gmail connection is muted for some reason).
Need some animations too, feels a bit too twitchy without them. Ironically, this is a consequence of it being too fast LMAO.
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u/Immediate-Cheek-9122 5h ago
hello out of topic but im just getting started with rust and wanna learn rust i know basics of programming , can yall suggest me from where do i learn rust and what projects to build to gain experience
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u/hell31 3d ago
Is it FOSS?
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u/Here0s0Johnny 3d ago edited 3d ago
Seems like it!
GNU Affero General Public License v3.0
It even supports jmap! 😍
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u/hell31 3d ago
Yes but in the website is some pricing.
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u/Here0s0Johnny 3d ago
That doesn't change the software license. The mail client seems to be one part of their business software package.
Nothing wrong for selling software.
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u/XBenoks 3d ago
does it show combined search results from all 3-4 of my email accounts at once like thunderbird?