The specification as-written is really, really bad (though I don't think this is a fault of the protocol),
Synapse is kind of...and work on Dendrite seems to have mostly stalled,
the billion people signed up on matrix.org has allowed for a sort of de facto centralization (not a huge problem, though in practice it sort of is, given how much the server buckles under the weight of all of the users; might be solved if it's ever moved onto a more performant implementation?),
the lack of encryption by default is iffy (though done for understandable reasons).
To lend credence to the specification being bad:
"I tried writing a matrix homeserver but I couldn't figure out how the state resolution process works" said by the author of Audacious/one of the authors of Pleroma/much more, so certainly a person who should be able to understand something that simple:
https://socially.whimsic.al/notice/9oxtjVqQw8gRS6QDKa
I know multiple people who've tried to implement the spec but who have gotten stuck on things that should be simple but are unclear if going by the spec.
> The specification as-written is really, really bad
We get a pretty wide range of feedback on the spec fwiw: some people seem to really like it. Others say that it’s “really, really bad” which doesn’t exactly give us much to go on...
> Synapse is kind of... and Dendrite is stalled
We have no choice but improve Synapse currently, and while it is still quite a resource hog it’s improved by at least 3-5x over the last year. Dendrite instead has become more of an R&D project for future homeserver shapes, but it’s not entirely stalled.
> The matrix.org server causes de-facto centralisation
The server has been less than 50% of the visible network for several years now - and ironically the datacenter perf issues (unrelated to Synapse) we had over the last few months have shifted that balance further - it’s about 35% and dropping. Ideally we will turn it off entirely once we have decentralised accounts.
> lack of e2ee by default is iffy
Our main project right now is to fix this. Cross-signing is mid flight; E2E search is done; Pantalaimon (E2E compat for dumb clients) is done; remaining key distribution bugs are in flight. We’re aiming to turn it in by default in Jan.
> “I couldn’t figure out how the state resolution works”
State resolution is the main technical novelty in Matrix, and yeah - it’s hard, much like git’s merge resolution is not exactly easy either. Unfortunately it comes with the territory; if you want to have consistent room state while replicating them over a byzantine network of servers to stop hijacks and other abuse, you have a relatively hard problem to solve. We got it wrong the first time; the current version gets it right (as far as we know).
The spec (which is deliberately formal and terse) is https://matrix.org/docs/spec/rooms/v2
However, there are supporting documents linked from the spec to help clarify: the original spec proposal at https://github.com/matrix-org/matrix-doc/blob/erikj/state_re... and the guide at https://matrix.uhoreg.ca/stateres/reloaded.html etc
Ironically I think that state res is one of the best documented and understood bits of Matrix now (which is just as well, given how important it is).
Why do you have no choice but improve Synapse?
One of the reasons you seem to only get negative opinions along the lines of "really, really bad" is because "The way it's written is stylistically bad/unapproachable and an entirely different approach should probably be taken" is something that takes a few hours to diffuse into something useful, and not something most people really receive in a way that's productive. It takes a lot more effort to give truly constructive, workable criticism than expressing any sort of opinion, negative or positive.
thanks :)
> Why do you have no choice but improve Synapse?
There are quite a lot of Synapses out there right now, and Synapse's featureset is pretty mature. Given we have pretty high profile people running Synapse (e.g. all of the French government) we have no choice but to invest the time to polish it and make it more efficient and stable. In an ideal world we'd have paused on Synapse ages ago and focused purely on a next-gen server, but we can't leave Synapse users in the lurch. Dendrite will be getting some attention in the coming months though, but not as a direct Synapse-replacement, but more of a playground for more experimental stuff.
> It takes a lot more effort to give truly constructive, workable criticism than expressing any sort of opinion, negative or positive.
True. fwiw, my guess is that kaniini was trying to implement state resolution before we published the first stable Server-Server API back in Feb - where it most certainly was the weakest part of the spec (and had design flaws too, which is why we hadn't bothered speccing it in detail).
After more than two years in and around this space I'm still comfortable with stating that I'd take Matrix with all^wmost its flaws over ActivityPub. All of these protocols kind of suck. I see Matrix as having the lowest hamming distance between where it is and where it should be.
protocol-wise, which flaws are currently the most egregious from your pov? (i.e. `all - most = ?`) (And if any are security issues, please chuck them to security@)
Before I'm accused of being unfair because there's always going to be a ridiculous ratio for something like a "hi" message, consider some alternatives for both the format and payloads of the fundamental protocol primitives. Most of the messages contain cryptographic metadata which has a succinct binary representation, but JSON requires base64; when represented naturally with CBOR the overhead can be reduced ~40%, and without encoding/decoding either. Consider that virtually all of the overhead in "hi" is either cryptographic hashes or signatures or integers (depth/ts) which would benefit from compact formats.
Does representation actually matter though? Why can't I just store Matrix in my format and federate with your format? I guess this is an example of where theory and reality collide. One cannot write a server which handles messages as abstractly as possible (leveraging these JSON/CBOR extensible formats) while at the same time knowing which fields have a more efficient binary representation and transforming that. In reality that just looks like a CBOR message with a bunch of base64 plaintext strings. It doesn't achieve that 40%.
All of this is important because of Matrix's (superior) design over its event abstraction. When the whole protocol is hinged on fundamental primitives (a good thing) attention to detail and focus must be given to those primitives. The more optimized they are, the more everything built with them is also optimized. When the foundation is efficient, developers can do more with matrix and enrich the user experience. For another example, matrix has been reluctant to give developers the power to store shared-program (i.e bot) state efficiently in a chat room. This is because there's no mechanism to delete state_keys, or even discard overwritten state itself. That's an important cornerstone that's missing while the rest of the tower is being piled on.
It might be possible to confuse any of these issues as trivialities, and their solutions as bike-shedding. I contest their importance is evident in how they emerge to shape the character of the entire system. Consider: does matrix require the entire DAG to be acquired like a bitcoin block-chain? Then I better be careful and conservative about messages. Does matrix allow gaps in the DAG and have a smaller chain for auth? Then I can be liberal about messages and delete stuff later. When I go to build an application which communicates over Matrix those qualities emerge as fundamental limitations or liberations of what users can experience.
