Open Source Slack AlternativesTop Group Chat Apps & Instant Messengers like Slack

Alternatives list

1. 

   

   Element

    845 likes

   Provides secure collaboration with end-to-end encryption, supporting chat, voice, and video calls. Available on all major platforms, it enables digital sovereignty with a decentralized design and interoperability through bridges to systems like Slack and Teams. Includes enterprise-grade SaaS.

   358 Element alternatives

   Cost / License

   • Free Personal
   • Open Source (AGPL-3.0)

   Application typeApplication types

   • Instant Messenger
   • Video Calling

   Origin

   • United Kingdom

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • iPhone
   • Android Tablet
   • iPad
   • Self-Hosted
   • Snapcraft
   • Matrix.org
   • Flathub
   • F-Droid
   • OpenAPK
   • Cloudron

   • United Kingdom

   

   

   

   +3

   

   More about Element  

   

   Good alternative?Is Element a good alternative to Slack?

    

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   13comments

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   Element vs Slack Comments

   Top Positive Comment by brinerustle · Mar 3, 2018

   because its open source, decentralised, and end-to-end secure. Plus the folks at matrix.org are working to get us out of our communication silos by creating standards for communication interoperability!

   Top Negative Comment by davaga6837 · Sep 18, 2025

   Element is way too buggy and slow. It's actually totally free unlike the description which says it's not free. But, free isn't enough when the software is just buggy and slow.

   Positive comment by Dserver Hosting · Dec 20, 2022

   this is a open source and free software that is very useful for me

   3 of 13 comments

   

   

   • Element is Free Personal and Open SourceSlack is Freemium and Proprietary
   • Element is an Instant Messenger Slack is a Group Chat App
   • Element is Decentralized, Privacy focused and LightweightSlack is not according to our users
2. 

   

   Matrix

    419 likes

   Open standard protocol enabling decentralized, encrypted instant messaging, VoIP signaling, IoT device connectivity, and persistent data management across federated servers without central control or single points of failure, bridging communication platforms.

   201 Matrix alternatives

   Cost / License

   • Free
   • Open Source

   Application typeApplication types

   • Instant Messenger
   • Group Chat

   Origin

   • United Kingdom

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • iPhone
   • Android Tablet
   • iPad
   • Self-Hosted
   • WebRTC
   • Python
   • JavaScript
   • Go (Programming Language)
   • Cloudron
   • Java
   • Perl

   • United Kingdom

   

   

   More about Matrix  

   

   Good alternative?Is Matrix a good alternative to Slack?

    

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   7comments

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   Matrix vs Slack Comments

   Top Positive Comment by Vladimir Studinsky · Oct 28, 2017

   Open source, fecentralized, federation, chat-voice-video function.

   Top Negative Comment by somegirlfromit · Sep 15, 2019

   Matrix is a protocol, not a client.

   Positive comment by Guest · Nov 3, 2017

   Respects your Freedom. Increasingly popular

   3 of 7 comments

   

   

   • Matrix is Free and Open SourceSlack is Freemium and Proprietary
   • Matrix is an Instant Messenger Slack is a Group Chat App
   • Matrix is Decentralized, Privacy focused, Security-focused and LightweightSlack is not according to our users
4. 

   

   Stoat Chat

    146 likes

   Instant messaging platform supporting text and voice channels, live video calls, secure screen sharing, private group chats, customizable permissions, moderation tools, bot integration, privacy-focused design, open-source development, and cross-platform use.

   86 Stoat Chat alternatives

   Cost / License

   • Free
   • Open Source

   Application typeApplication types

   • Group Chat
   • Instant Messenger

   Origin

   • United Kingdom

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • Android Tablet
   • Rust
   • F-Droid

   • United Kingdom

   

   

   

   +3

   

   More about Stoat Chat  

   

   Good alternative?Is Stoat Chat a good alternative to Slack?

    
5. 

   

   Wire

    334 likes

   Secure communication platform featuring encrypted chats and calls, file and media sharing, self-deleting messages, device verification, group collaboration, and customizable settings. Supports use across multiple devices with no phone number required for access.

   307 Wire alternatives

   Cost / License

   • Free Personal
   • Open Source (GPL-3.0)

   Application typeApplication types

   • Instant Messenger
   • Video Calling

   Origin

   • Switzerland

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • iPhone
   • Android Tablet
   • iPad
   • Self-Hosted
   • Snapcraft
   • Flathub
   • F-Droid
   • Software as a Service (SaaS)
   • OpenAPK

   • Switzerland

   

   

   

   More about Wire  

   

   Good alternative?Is Wire a good alternative to Slack?

    
6. 

   

   Zulip

    276 likes

   Threaded group conversations combine live and asynchronous messaging, separating topics for organized collaboration, supporting open-source, cloud, and self-hosted deployments, secure communication with encryption, and multi-platform access for diverse teams.

   253 Zulip alternatives

   Cost / License

   • Free Personal
   • Open Source (Apache-2.0)

   Application typeApplication types

   • Instant Messenger
   • Group Chat

   Origin

   • United States

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • iPhone
   • Android Tablet
   • BSD
   • iPad
   • Self-Hosted
   • F-Droid

   • United States

   

   

   

   +4

   

   More about Zulip  

   

   Good alternative?Is Zulip a good alternative to Slack?

    

   |

   78comments

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   Zulip vs Slack Comments

   Top Positive Comment by Paulo Coghi · Feb 6, 2020

   More than feature parity with Slack, it's better because of Streams and Topics. It offer the same free tier with 10.000 max messages and better paid plans to the hosted version, and also provide the open source self-hosted option to install it on your own server and also remove the max messages limits. 5 stars

   Positive comment by lamyseba · Mar 22, 2026

   Zulip messages are organized by channel and by topic, wich is very efficient for our usecase. If a message get in wrong channel/topic, you can manage to move it to the right place. Last but not leat: Zulip is Open source and available on mobile app, native app and web browser. The mobile app has a few less feature than browser/native app

   Positive comment by Nakul Verma · Jan 29, 2026

   Zulip is a very good free and open source software that helps people to conversation to each other on random and some important topics separately. A usercan see who is online or ofline at the real time that is awesome.

   3 of 78 comments

   

   

   • Zulip is Free Personal and Open SourceSlack is Freemium and Proprietary
   • Zulip is an Instant Messenger Slack is a Group Chat App
   • Zulip is Privacy focused and LightweightSlack is not according to our users
8. 

   

   Threema

    148 likes

   Threema is a new mobile messaging app that puts security first. With true end-to-end encryption, you can rest assured that only you and the intended recipient can read your messages.

   143 Threema alternatives

   Cost / License

   • Paid
   • Open Source

   Application typeApplication types

   • Instant Messenger
   • Encrypted Chat

   Origin

   • Switzerland

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • iPhone
   • Android Tablet
   • HUAWEI AppGallery
   • iPad
   • Flathub
   • F-Droid

   • Switzerland

   

   

   

   More about Threema  

   

   Good alternative?Is Threema a good alternative to Slack?

    
9. 

   

   Armada

    17 likes

   Open-source, end-to-end encrypted chat supporting decentralized, serverless communities and Concord. Features self-hosting, cryptographic login, encrypted text channels, threads, live voice and video rooms, compatibility with Nostr and other protocols, custom emojis, and GIFs.

   Cost / License

   • Free
   • Open Source (AGPL-3.0)

   Application typeApplication types

   • Video Calling
   • Instant Messenger

   Origin

   • United States

   Platforms

   • Mac
   • Windows
   • Linux
   • Online
   • Android
   • iPhone
   • Self-Hosted

   • United States

   

   

   

   +1

   

   More about Armada  

   

   Good alternative?Is Armada a good alternative to Slack?

    
10. 

    

    Element X

     51 likes

    It is the brand new, and fastest ever, Matrix client. It is for personal and community use, and will support enterprise functionality later this year.

    141 Element X alternatives

    Cost / License

    • Free
    • Open Source (AGPL-3.0)

    Application typeApplication types

    • Instant Messenger
    • Video Calling

    Origin

    • United Kingdom

    Platforms

    • Android
    • iPhone
    • Android Tablet
    • iPad
    • Android Auto
    • OpenAPK

    • United Kingdom

    

    

    

    More about Element X  

    

    Good alternative?Is Element X a good alternative to Slack?

     
11. 

    

    Rocket.Chat

     163 likes

    Open-source chat server supporting real-time group, direct, and private messaging, video calls, file sharing, helpdesk chat, API integrations, desktop notifications, emojis, LDAP authentication, cross-platform apps, and customizable extensions for teams.

    169 Rocket.Chat alternatives

    Cost / License

    • Freemium
    • Open Source (MIT)

    Application typeApplication types

    • Group Chat
    • Instant Messenger

    Origin

    • United States

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • iPad
    • Self-Hosted
    • Cloudron
    • Snapcraft
    • Android Tablet

    • United States

    

    

    

    +5

    

    More about Rocket.Chat  

    

    Good alternative?Is Rocket.Chat a good alternative to Slack?

     

    |

    3comments

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    Rocket.Chat vs Slack Comments

    Positive comment by John Fastman · Dec 26, 2016

    Does everything Slack does AND it's open source. However, it's also self-hosted. This means you have to put in the effort to set it up, but you control your own data, which is a huge advantage to your privacy - your chats and files don't sit on someone else's servers, ready for them or hackers to look at.

    Positive comment by Guest · Jun 17, 2018

    Rocket.Chat comes very close to slack regarding it's core features and handling.

    Positive comment by Guest · Nov 29, 2018

    open source, locally hosted so you own your data.

    3 of 3 comments

    

    

    • Rocket.Chat is Freemium and Open SourceSlack is Freemium and Proprietary
12. 

    

    Conversations

     107 likes

    Conversations is a privacy focused, open source XMPP Texting [Jabber] client for Android 4.0+ smart phones with wife-approved easy encryption [OTR, OMEMO, or GPG].

    166 Conversations alternatives

    Cost / License

    • Free
    • Open Source (GPL-3.0)

    Application typeApplication types

    • Instant Messenger
    • Group Chat

    Origin

    • Germany
    • EU

    Platforms

    • Android
    • Android Tablet
    • F-Droid

    • Germany
    • EU

    

    

    

    +4

    

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13. 

    

    Quiet Chat

     23 likes

    Peer-to-peer group chatting over Tor and IPFS, with local-first encrypted messaging and no central servers, offers privacy-focused decentralized collaboration for teams, supporting desktop and mobile. FOSS, open to contributors, and avoids surveillance-based tracking.

    Cost / License

    • Free
    • Open Source (GPL-3.0)

    Application typeApplication types

    • Group Chat
    • Encrypted Chat

    Origin

    • United States

    Platforms

    • Mac
    • Windows
    • Linux
    • Android
    • iPhone
    • Android Tablet
    • iPad

    • United States

    

    

    More about Quiet Chat  

    

    Good alternative?Is Quiet Chat a good alternative to Slack?

     
14. 

    

    Buzz

     6 likes

    Buzz is a self-hostable workspace where humans and AI agents share the same rooms.

    64 Buzz alternatives

    Cost / License

    • Free
    • Open Source (Apache-2.0)

    Application typeApplication types

    • Group Chat
    • Video Calling

    Origin

    • United States

    Platforms

    • Mac
    • Windows
    • Linux
    • Self-Hosted
    • Docker
    • AppImage
    • iPhone

    • United States

    

    

    

    +1

    

    More about Buzz  

    

    Good alternative?Is Buzz a good alternative to Slack?