Free picks · Mac · Open source
Best free open-source communication apps for Mac (2026)
Every pick is listed under Communication in our directory, runs on a Mac and is free to use and tagged open source. We rank them by our rating and popularity, then favour tools made mainly for communication and apps built for Mac.
Short answer
The best free open-source communication apps for Mac are Ferdium, Flameshot and Mattermost, the top three of 14 matches in our directory. All 10 are tagged open source in our directory. 5 of the 10 picks are completely free and the other 5 have a free plan.
Updated
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At a glance
Counted from the top 10 picks, except the total.
- Matching tools
- 14
- Completely free
- 5
- Open source
- 10
- Work offline
- 5
- Native apps
- 6
Comparison table
“Free plan” means a free tier with paid upgrades. A dash in Licence means our directory does not list the tool as open source.
| # | Name | Pricing | Platforms | Licence | Why pick it |
|---|---|---|---|---|---|
| 1 | Ferdium | Free | Windows, macOS, Linux | Open source | All your messaging and work apps together in one desktop window. |
| 2 | Flameshot | Free | Linux, Windows, macOS, Offline | Open source | An open-source screenshot tool with quick, built-in annotation. |
| 3 | Mattermost | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Self-hosted, open-source team chat with a free edition for small teams. |
| 4 | Thunderbird | Free | Windows, macOS, Linux, Android, Offline | Open source | A free, open-source email client for managing several inboxes in one place. |
| 5 | Zulip | Free plan | Web, macOS, Windows, Linux, iOS, Android | Open source | Open-source team chat where every conversation has a topic, so threads stay readable. |
| 6 | Mumble | Free | macOS, Windows, Linux | Open source | Low-latency voice chat you can run on your own server. |
| 7 | Rocket.Chat | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Open-source team chat you host yourself, free for up to 50 users. |
| 8 | Element | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Open-source, Matrix-based messaging you can self-host for free. |
| 9 | Big Arrow on the Screen | Free | macOS | Open source | Let AI agents point at the exact button you need to click with big on-screen arrows. |
| 10 | Mailspring | Free plan | macOS, Windows, Linux | Open source | A fast, open-source email app with snooze and send later. |
Why each pick made the list
Every reason is taken from the tool's own listing: its categories, platforms, features, rating and pricing.
Our top Mac pick, rated 4.5/5. Made mainly for communication, one of 7 such picks here. A desktop app that runs on a Mac, and also on Windows and Linux. Its listing says it is privacy-focused (7 of 10 here) and is easy to pick up (4 of 10 here). It is not in the iPhone top 9 (not listed for iPhone). On the wider free Mac list, open source or not, it is number 2.
Watch out for: Each service runs as a web view, so it can use a lot of memory
Number 2 of 10 for Mac, rated 4.6/5, the highest here. Made mainly for communication, one of 7 such picks here. A desktop app that runs on a Mac, and also on Linux, Windows and Offline. Its listing says it works offline (5 of 10 here) and is easy to pick up (4 of 10 here). It is not in the iPhone top 9 (not listed for iPhone). On the wider free Mac list, open source or not, it is number 3.
Watch out for: No screen recording
Number 3 of 10 for Mac, rated 4.4/5. Made mainly for communication, one of 7 such picks here. Runs on a Mac, and also on Web, Windows, Linux, iOS and 1 more platform. Its listing says it is privacy-focused (7 of 10 here). On our iPhone list it is number 1. On the wider free Mac list, open source or not, it is number 8.
Watch out for: You need to run and maintain your own server
Number 4 of 10 for Mac, rated 4.5/5. Made mainly for email, it is one of 3 picks here that cover communication as a second use. A desktop app that runs on a Mac, and also on Windows, Linux, Android and Offline. Its listing says it works offline (5 of 10 here), is privacy-focused (7 of 10 here) and is easy to pick up (4 of 10 here). It is not in the iPhone top 9 (not listed for iPhone). On the wider free Mac list it ranks 11th, outside the top 10.
Watch out for: Interface can feel busy at first
Number 5 of 10 for Mac, rated 4.5/5. Made mainly for communication, one of 7 such picks here. Runs on a Mac, and also on Web, Windows, Linux, iOS and 1 more platform. On our iPhone list it is number 2. On the wider free Mac list it ranks 12th, outside the top 10.
Watch out for: Free cloud plan only searches the latest 10,000 messages
Number 6 of 10 for Mac, rated 4.4/5. Made mainly for communication, one of 7 such picks here. A desktop app that runs on a Mac, and also on Windows and Linux. Its listing says it works offline (5 of 10 here) and is privacy-focused (7 of 10 here). It is not in the iPhone top 9 (not listed for iPhone). On the wider free Mac list it ranks 16th, outside the top 10.
Watch out for: Voice only
Number 7 of 10 for Mac, rated 4.2/5. Made mainly for communication, one of 7 such picks here. Runs on a Mac, and also on Web, Windows, Linux, iOS and 1 more platform. Its listing says it is privacy-focused (7 of 10 here). On our iPhone list it is number 3. On the wider free Mac list it ranks 18th, outside the top 10.
Watch out for: Self-managed only on the free plans, so you need technical setup
Number 8 of 10 for Mac, rated 4.3/5. Made mainly for communication, one of 7 such picks here. Runs on a Mac, and also on Web, Windows, Linux, iOS and 1 more platform. Its listing says it is privacy-focused (7 of 10 here). On our iPhone list it is number 4. On the wider free Mac list it ranks 19th, outside the top 10.
Watch out for: Self-hosting needs technical setup
Number 9 of 10 for Mac, rated 4.4/5. Made mainly for AI productivity, it is one of 3 picks here that cover communication as a second use. A Mac app that runs on a Mac and nowhere else. Its listing says it works offline (5 of 10 here). It is not in the iPhone top 9 (not listed for iPhone). On the wider free Mac list it ranks 20th, outside the top 10.
Watch out for: macOS only
Number 10 of 10 for Mac, rated 4.5/5. Made mainly for email, it is one of 3 picks here that cover communication as a second use. A desktop app that runs on a Mac, and also on Windows and Linux. Its listing says it works offline (5 of 10 here), is privacy-focused (7 of 10 here) and is easy to pick up (4 of 10 here). It is not in the iPhone top 9 (not listed for iPhone). On the wider free Mac list it ranks 22nd, outside the top 10.
Watch out for: Tracking and analytics need the Pro plan
Running these on Mac
Counted from each pick's listing type and platforms.
- By listing type, the 10 Mac picks are 5 desktop apps (Ferdium, Flameshot, Thunderbird, Mumble and 1 other), 4 web apps (Mattermost, Zulip, Rocket.Chat and Element) and 1 Mac app (Big Arrow on the Screen).
- 6 of 10 are apps you install on a Mac, and Big Arrow on the Screen is made specifically for Mac; the other 4 are web or cloud tools listed for Mac.
- Big Arrow on the Screen is listed for Mac and nothing else. Element reaches furthest, on 5 other platforms besides Mac.
- 4 of 10 also run on iPhone and iPad, so the same tool can follow you between Mac and iPhone; Ferdium, Flameshot, Thunderbird, Mumble and 2 others do not.
How this list compares
The same search on other platforms, and the other price filter. Only the differences are named.
- Free open-source communication apps for iPhone
4 of these 10 Mac picks also make the iPhone top 9. 6 are on this list only: Ferdium (not listed for iPhone), Flameshot (not listed for iPhone), Thunderbird (not listed for iPhone), Mumble (not listed for iPhone), Big Arrow on the Screen (not listed for iPhone) and Mailspring (not listed for iPhone). In their place the iPhone list has Farcaster, Jami, Mastodon, Jitsi Meet and Lemmy; Farcaster, Mastodon, Jitsi Meet and 1 other are not listed for Mac.
- Free communication apps for Mac
Fine with closed source? The wider free Mac list ranks 32 tools that run on a Mac, open source or not, led by Discord, Ferdium and Flameshot.
More matches
4 more free open-source communication apps for Mac in our directory, in ranked order.
Frequently asked questions
- What is the best free open-source communication app for Mac?
- Ferdium is our first pick. All your messaging and work apps together in one desktop window. Yes. Ferdium is free to use.
- Are these communication apps really free?
- Yes, every pick is free to start. Ferdium, Flameshot, Thunderbird, Mumble and 1 other are completely free. Mattermost, Zulip, Rocket.Chat, Element and 1 other have free plans with paid upgrades.
- Do these open-source communication apps work on other platforms too?
- 9 picks of 10 also run elsewhere, including Ferdium (Windows and Linux), Flameshot (Linux, Windows and Offline) and Mattermost (Web, Windows and Linux).
- Which ones work offline on a Mac?
- Flameshot, Thunderbird, Mumble, Big Arrow on the Screen and Mailspring are listed as working offline. The others need an internet connection for at least some features.
- Which are easiest for beginners?
- Ferdium, Flameshot and Thunderbird are rated beginner-friendly, along with 1 other pick. 6 picks take more time to learn.
- How many free open-source communication apps for Mac are in the directory?
- 14 match: listed under Communication, available on a Mac and free to start, and tagged open source. This page ranks the top 10 and names up to 20 more under More matches. The Communication category page has every listing, paid ones included.
Keep exploring
Wider lists
Related free lists
- Free communication apps for Mac
- Free communication apps for iPhone
- Free note-taking apps for Mac
- Free communication apps for Linux
- Free to-do list apps for Mac
- Free open-source communication apps for iPhone
- Free project management apps for Mac
- Free time management apps for Mac
- Free writing apps for Mac
- Free AI productivity tools for Mac
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