Nheko is not perfect and lacks polish in some places, but I like it a lot, and it supports cross-signing.

Appreciate the comment, last time I tried it all of this was missing. Seems like it's a fully fledged alternative now.

I'll try it out. Seems like they implemented most code in a mtxclient library, so it might be possible to reuse it for other clients.

mtxclient mostly implements the API calls and some crypto primitives. A lot of stuff still lives in Nheko, because we couldn't figure out how to fit it neatly into mtxclient (like the storage layer, device verification flows, etc). But apart from that, probably. It is pure C++, so you don't even need to use Qt to create a client with it. (In general it may be better to contribute to an existing client though. There are a lot and they could use some help to become more polished.)

I've been reading the Nheko updates in This Week in Matrix with enthusiasm. How are E2EE and cross-signing coming along? Once those parts are fully implemented, stable, and trustworthy, it will look pretty attractive as a replacement for Element desktop.

They are implemented, but I would say there are still bugs in it and it isn't yet 100% trustworthy. Moving E2EE out of beta is one of the goals for the next release though. There are still some minor kinks, but I have been using Nheko as my primary client for E2EE chats for 2 years now. I wouldn't trust it if you know someone is actively trying to get at your data, but for normal day to day chats the current master branch should be good enough.

Things that are currently still missing: - online key backup: The asymmetric version allows server operators to insert keys and the symmetric one isn't yet supported by any client. I don't use key backup on my account, since I have enough devices that I don't need it and it makes bugs in E2EE harder to find. - cross-signing bootstrap: You need Element to enable cross-signing on your account once atm. - A toggle to only send keys to verified devices in a room and warnings if unverified devices are in a room: currently working on this - Fixing one stupid edge case, where we create new identity keys by mistake, if Nheko fails to open the database and this breaks E2EE for that login. Hard to hit by accident, but it happens quite a lot if you change database code and mess something up. :D

I think apart from that we are in somewhat good shape. I still have a few small things on my to do list and we obviously need to go through the code a few more times to look for mistakes and test it a lot more, but for 0.9.0 that should be doable. After 0.9.0 we'll probably look into fallback keys as well as dehydrated devices.

I can vouch for Nheko. It’s fast as well (native code with Qt?).

Yes, most of it is Qt quick, some parts are still Qt widgets AFAIK.

Subjectively speaking, it's one of the fastest and most fully-featured clients: it even supports desktop sharing with pipewire and gstreamer.

It's a lot easier to use once you get used to the Ctrl+K shortcut to select a room.

Good: FluffyChat's CPU usage has been reduced so it no longer burns CPU (nor makes Xorg burn CPU) when idle, only when typing or moving your mouse (with call stacks deep in Flutter event handling).

Bad: It's written in Flutter, and the keyboard/mouse handling still has flaws.

Ugly: The FluffyChat Matrix library used by FluffyChat (https://pub.dev/packages/matrix) requires contributors to sign a CLA where you sign away copyrights/trademarks, and perhaps even become obligated to assist the Famedly company in IP lawsuits.

The Rust rewrite is stalled but not abandoned, there's just been a bit of a slump due to time constraints. Which features are you missing the most?

Schildichat works between devices, I get notifications on both riot.im element and schildichat on Android, as well as on my desktop.

Maybe I am unclear of what cross device signing is