Apart from already mentioned Mattermost[0] and rocket.chat[1], Matrix[2] and their main client Riot[3] is seriously worth checking out. It's a quite ambitious effort for decentralized, federated IM / group communication. There's still some work left on the protocol in terms of federated identity, which should not be necessary of you're looking to replace Slack. I haven't spent significant time with it in the past year or so, but from my understanding it's starting to become production ready.

IMO there's value in pushing for decentralized, federated alternatives. Would be interested to hear from people who have used it in anger.

[0]: https://mattermost.com/ [1]: https://rocket.chat/ [2]: https://matrix.org/ [3]: https://about.riot.im/

Mattermost is a self hosted clone, zulip is an option too although it's not a direct copy. We've also used discord and MS teams

Mattermost is really nice, and is self-hosted. If you run a self-hosted version of GitLab as well, the GitLab omnibus may be interesting, because it contains Mattermost as well.

https://docs.gitlab.com/omnibus/

Indeed this makes upgrading the whole enchilada a breeze.

Watch out though, the MM database is not backed up by the GitLab backup scripts.

The script I wrote: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/2493

The general issue tracking vendored software backup: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1927

MS Teams has decent video but everything else about is hugely inferior to Slack in my experience. Very frustrating.

I've also hosted a few mattermost instances, highly recommended. It's a YC company too which is cool.

I like that you can choose to use the smartphone app, desktop app or the web app - just like slack except you host it.

We used Zulip in a previous team and it was great. The topics system is the killer feature (like a much better version of Slack's threads).

The mobile apps weren't brilliant 9 months ago, but they were in the early stage of a rewrite in react native, so the situation has likely improved as that has matured.

Zulip's topic system looks fantastic for keeping things organised over time. I wish we could use it instead of Slack.

That's definitely true, but the time it really shines is when there's been a lot of conversation on a few different things while you've been away. In Slack, you basically have to read every message to see if there was anything of importance to you. In Zulip you just flick through the topics to see which ones are relevant and only read those.

We use zulip and most of the time the topic thing is used by accident. We also tried slack but it was too bloated. Honestly hip chat was the best platform we ever used. Maybe we will try rocket chat.

> the topic thing is used by accident

It has been designed to be used with the topics and there is no workflow that allows you to avoid topics. I'm not sure what you mean by using topics by accident.

probably started with a 'general' topic and people never created other topics.

Have you looked at ripcord? (https://cancel.fm/ripcord/) It's not the most amazing UI right now, but it's light and functional. And it works with the existing slack service.

Otherwise, have you tried contacting Slack? They've done a lot of improvements recently. My memory usage in FF barely goes over 30mb normally. If you're way over that, maybe you're running into some specific bug they'd want to fix.

Seconded. It's not amazing UI in terms of modern design sensibilities, but to me, it's an improvement over Slack. Snappier, higher information density. And, of course, very lightweight.

Hi all! Check out Openland. We are YC W18 company and are building a next-generation general-purpose messenger. It completely replaced Slack for us internally (remote team of 12). Totally free now.

What we have:

    Apps for every platform
    Voice calls and conferences
    Group chats and channels
    Mentions, replies, forwards
    Emojis, emoji reactions, and stickers
    Threaded comments
    Link previews
    Rich text formatting
    Keyboard shortcuts
    File attachments and previews
    Message search

Invite: https://openland.com/invite/h2BGtL

Is there a landing page? I'm getting redirected to the invite page when opening openland.com

I think few people (especially on HN) are okay with giving away their email without seeing at least a glimpse of what your app is doing.

Current landing page: https://openland.com. A new landing page is coming soon.

Use the invite above to sign up and bypass the waitlist.

Opened it, I can only see an unicorn. There's an error on the console: "Notification is not defined" at main-9cc8c714bb9b9a687b5f.js:1:4562

Looking into it. Can be a connectivity issue.

Are you building on the Matrix protocol? In case you decided not to, what made you decide against it?

Openland is great

Keybase.io is free and encrypted. Subteams, chat, file sharing and encrypted git support.

And oddly enough, a cryptocurrency wallet now.

They give you free money for some reason. I was priding myself on never having any crypto holdings until they forced the cash on me (which, of course, cannot be complained about on a basis of principle).

It does create headaches for those of us who have to report gifts and extramural income sources.

Not really true, they only distribute it for users who have initiated the wallet set-up AFAIK.

Discord (https://discordapp.com/)

Discord probably has a similar overhead, since neither are native apps but use Electron instead.

It's way better though. None of this weird threaded discussions and other annoying lock-in features.

Threaded discussions are a god-sent in most teams I've worked with. It allows keeping conversations nice and tidy or just ignore the ones you don't care about.

If you work in the Microsoft ecosystem, Teams is the obvious answer. On my machine it currently hovers around 82MB.

I have used Teams before, but it's not smooth. Had a lot of UX cramps.

How long ago?

We've been using Teams for about 18 months since switching from Slack due to its prohibitive cost across our whole org[1]. Whilst Teams is far from perfect, it's got considerably better during that time.

[1] We'd reached the point where the 10000 message limit on the free plan meant our history was down to a few days, which meant that important messages were getting lost whilst they were still needed.

On macOS the UI is pretty crampy.

Fair comment: I've only ever used it on Windows and iOS. My personal machines are Macs but I never use Teams on them.

>We'd reached the point where the 10000 message limit on the free plan meant our history was down to a few days

Why not pay for it? It's $6.67 per person, per month. Doesn't seem very expensive for a company.

Expensive isn't really the issue. For a (reasonably sized) company (earning decent revenue) plenty of things aren't expensive in isolation. The problem is that there are a lot of things a company either needs or wants to spend money on, so at some point you have to start prioritising.

For us, we need single sign-on, so Slack's £9.75/user/mo. For 200 users that's nearly £2000/month, or £24000/year.

We're now nearly 300 people. That's about £35000/year. And it only gets worse as the company grows.

That's more - I mean, way more - than it costs us to license SQL Server (amortised annually on a 3 year upgrade cycle). It's more than the licenses for several of our other business critical systems and services combined.

In terms of priorities then, we're about to embark on a series of infrastructure improvements and I'd much rather use that £35,000 there, where for us it can add more value.

The problem with Slack is it sounds cheap but the cost creeps up to quite substantial levels for even relatively small organisations. It then needs to be weighed against other costs, and the value it provides versus the value they provide.

Whereas on the other hand we're already paying for Office 365, which everybody in the company uses heavily every working day of the year, and Teams is bundled with it, and it does everything we need, so why not use it?

Damn, I can agree with you. 35k per year is a hell lot for collaboration software.

I was forced to use for a customer project around ~8months ago

I found it to be a horrible product. Automatically, you get notifications from each channel, creating a private team is pretty much impossible, the threads are a bad feature and it's not possible to give people nicknames, which is really fucking annoying when it automatically tries to detect what a person's first name is and does it wrong.

Am I the only one who loads the website for some of these alternatives, see they use flat design and immediately closes the tab?

This isn't a slack alternative, per se, but I really like quip. It lets you create and share documents. You can then leave comments on a part of a document and tag other people, who will then get alerted. It lets you have conversations entirely within in the context of, for example, a design document. It would be perfect if it also had tight integration with a task tracker.

Odd to see that no one recommended ERC the emacs IRC extension

on a more serious note, TheLounge is pretty great as a self-hosted web-based irc client

Skype for Business. It's for business after all.

Skype for Business is obsolete, though:

https://www.theverge.com/2017/9/25/16360072/microsoft-teams-...

You may want to read up on Poe's law[0] on why sarcasm and irony are less effective than you might expect online.

[0] https://en.m.wikipedia.org/wiki/Poe%27s_law

Channels and private messaging: You can use IRC. It does that very well. (You don't even need a IRC client or any other specialized software; you can just telnet in and that works, and it was actually designed to be able to work without specialized software. However, using specialized software is better because it can auto-pong and can prevent what you type from getting mixed up with what someone else types.)

Share images and files: There are many ways to do this and it can be done independently of the chat system in use. (However, it would also be possible for a IRC client to include such integrated features, sending the URL so that other users can download whether or not they are using the same software as you do.)

Support for some of the automated commands you can integrate with Slack: Unfortunately, I do not understand.

We recently moved to using Basecamp for communication, it has a flat fee for as many team members you want which is pretty good for a growing company.

Real time Chat feature (Campfire) is built in which is great and intuitive.

However most of our team members are somehow still used to Slack chat interface.

Alternatives:

1. IRC, and share files and images through web-based sharing platforms and links.

Simple, low resource consumption, excellent instrumentation and automation possibilities, logging, etc. Downside - not as convenient as pasting shared content onto a channel. There are web-based IRC clients as well, but they're the opposite of private, and few of the benefits of standalone clients.

In extremely extensive use by many groups and organizations, despite not being fashionable.

2. Telegram (using the groups feature)

Kind of in the middle between Slack and IRC, I guess. Not sure you can use it from within the browser though.

Used, for example, by the LibreOffice development community (from which I noticed this kind of Slack-like use - the LTR/RTL QA volunteers have their own group.)

I would like an alternative too that uses a native app, not an Electron app preferably. Something that is very simple will be fine, but it needs to allow for drag and dropping pictures and documents.

Discord. Yes it's marketed towards gaming communities but it's still good for everything you mentioned

https://discordapp.com

Have you updated to the latest version of Slack? Mine is currently sitting at 222mb, which isn't great but it's significantly less memory hungry that it used to be.

Not free, but a lot of big corps seem to use Symphony: https://symphony.com/

I'm not a massive slack (or electron) fan but with it open right now in 7 teams it's using around 85mb of memory. It's improved a fair bit.

Slack is a mess for me. I have only 3 teams open but it will routinely freeze for 10-20 seconds and often will go into the hundreds of MBs.

No problem with Teams so clearly it isn't Electron.

https://www.flowdock.com , besides all the normal features you mentioned, it has excellent thread support, which is huge! So you can have multiple conversations in the same channel/flow during several days and can just ignore whichever thread isn't for you. We have been using it with a 100% remote team for over 6 years.

Jandi: https://www.jandi.com/

Covers most of the use cases of Slack, though a bit less automated commands.

It's cheaper and designed for a lot of enterprise things like factories, hospital, food industry. They don't advertise so much to the tech industry as it's hard to peel people from Slack.

disclosure: was paid to help them expand to SE Asia

Discord

It's marketed for gamers yes but bots, darkmode, all the features, all the compatibility, destroys slack in everyway imo

We briefly tried Discord at our company but found it had too high of a learning curve after previously using Teamwork Chat and Slack.

I guess if you're already a gamer then it makes sense.

Do you need a chat app?

What if your team just used a number of email mailing lists for channels, direct emails for private messaging, and having bots send notifications via email?

Emails give you rich content, asynchronous messaging, cross-platform support, history, threads, and more.

One of the nice things about slack (and it's alternatives) is that it is really easy to hop in a channel and see what is happening in a part of the company. Lots of times I find a bug or issue with an internal tool, and go to the related channel, and right away I can see they noticed the issue and are working on it. With email you don't have that kind of visibility unless you are sending company-wide emails every time there is an issue with some tool or system, and that doesn't scale very well.

Also it's nice to be able to search through history for things like error messages, or just keywords related to what I am working on. Plenty of times I have just searched for an error and found the solution right away, also not possible with email unless every single time you discussed an error message, those emails were sent to everyone (and then new hires still won't have access to data before they were hired).

No trouble ticketing system to track open/known issues?

No knowledge base/wiki system to share solutions and tips?

Or you can solve all the above by just archiving the mailing lists.

Agreed. I think we don't need real-time chat as much as we think. At not as the main mode of communication.

Twist seems like a good alternative.

Emails are a mess, especially when chains become unruly. Chat apps help alleviate that.

If anything, OP should consider jumping on IRC.

Check out https://guild.co. Quite different to Slack, more like a private professional version of WhatsApp. We use it to communicate with professional groups around topics.

Telegram works great. Free, privacy friendly, you can create channels (groups), supports bots, super fast with native apps, unlimited cloud storage, unlimited search history and more.

We've been using it for years in our company with excellent results

I didn't downvote but for a company-wide tool like that, I'd prefer a solution with a more established legal presence somewhere. Telegram seems more targeted at the consumer space.

Agreed, been using it for 5 years for around 30 of us in 5 to 7 teams. Drag and drop for upload, as well as desktop, mobile and web apps.

I just wanted to know why not installing the slack app? I have seen running any app in FF which polls data every few intervals is really difficult to maintain, it eats up all the memory and CPU.

The Slack app is Electron based and pretty bloated too in my experience. I want a native app.

But I think it's still better than running in FF.

Try https://web.ushare.to

- group chat and private messaging - video conferencing - share files - integration framework

Yeah, memory consumption. That's the problem.

Okay, buddy. Guess you'll need to "move away from" every web browser that loads Slack too, right?

Riiiiiiight...

Chatwork (https://www.chatwork.com/)

IRCCloud allows sharing images and files, and is compatible with IRC so people can join from other IRC clients as well if they want to

A total different approach: Twist.com I suggest reading about their approach to async communication and the blogs.

Twist from doist ? (I've not used it)

rocket.chat perhaps. But it is still a webapp so the memory consumption will perhaps be similar.

For us MS Teams works well. I haven't used Slack so I cannot compare the two.

Have been using rocket chat for couple of years without issues.

RingCentral App, even with phone calls and video conferences

My condo assoc. has used Glip for a few years on the free tier without any issue. You'll need to pay to get compliance exports.

Fleep.io

How does it compare to Floop.io?

2 letters are different.

flock.com? Haven't used but it will have features similar to Slack.