Free picks · Windows · Open source
Best free open-source communication apps for Windows (2026)
Every pick is listed under Communication in our directory, runs on a Windows PC 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 Windows.
Short answer
The best free open-source communication apps for Windows are ShareX, Mattermost and Zulip, the top three of 5 matches in our directory. All 5 are tagged open source in our directory. 1 of the 5 picks is completely free and the other 4 have a free plan.
Updated
Built with love by Shushant Lakhyani. Building bestproductivityresources.com
At a glance
Counted from the top 5 picks, except the total.
- Matching tools
- 5
- Completely free
- 1
- Open source
- 5
- Work offline
- 1
- Native apps
- 1
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 | ShareX | Free | Windows | Open source | Free, open-source screenshots, screen recording and GIFs for Windows. |
| 2 | Mattermost | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Self-hosted, open-source team chat with a free edition for small teams. |
| 3 | 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. |
| 4 | 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. |
| 5 | Element | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Open-source, Matrix-based messaging you can self-host for free. |
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 Windows pick, rated 4.7/5, the highest here. Communication is its main purpose in our directory. A Windows app that runs on a Windows PC and nowhere else. Its listing says it works offline. It is not in the Mac top 5 (not listed for Mac).
Watch out for: Windows only
Number 2 of 5 for Windows, rated 4.4/5. Communication is its main purpose in our directory. Runs on a Windows PC, and also on Web, macOS, Linux, iOS and 1 more platform. Its listing says it is privacy-focused. On our Mac list it is number 1.
Watch out for: You need to run and maintain your own server
Number 3 of 5 for Windows, rated 4.5/5. Communication is its main purpose in our directory. Runs on a Windows PC, and also on Web, macOS, Linux, iOS and 1 more platform. On our Mac list it is number 2.
Watch out for: Free cloud plan only searches the latest 10,000 messages
Number 4 of 5 for Windows, rated 4.2/5. Communication is its main purpose in our directory. Runs on a Windows PC, and also on Web, macOS, Linux, iOS and 1 more platform. Its listing says it is privacy-focused. On our Mac list it is number 3.
Watch out for: Self-managed only on the free plans, so you need technical setup
Number 5 of 5 for Windows, rated 4.3/5. Communication is its main purpose in our directory. Runs on a Windows PC, and also on Web, macOS, Linux, iOS and 1 more platform. Its listing says it is privacy-focused. On our Mac list it is number 4.
Watch out for: Self-hosting needs technical setup
Running these on Windows
Counted from each pick's listing type and platforms.
- By listing type, the 5 Windows picks are 4 web apps (Mattermost, Zulip, Rocket.Chat and Element) and 1 Windows app (ShareX).
- 1 of 5 are apps you install on a Windows PC, and ShareX is made specifically for Windows; the other 4 are web or cloud tools listed for Windows.
- ShareX is listed for Windows and nothing else. Element reaches furthest, on 5 other platforms besides Windows.
- 4 of 5 also run on Android, so the same tool can follow you between Windows and Android; ShareX does not.
How this list compares
The same search on other platforms. Only the differences are named.
- Free open-source communication apps for Mac
4 of these 5 Windows picks also make the Mac top 5. One is on this list only: ShareX (not listed for Mac). In their place the Mac list has Harper; it is not listed for Windows.
- Free open-source communication apps for iPhone
4 of these 5 Windows picks also make the iPhone top 6; the one that does not is ShareX.
Frequently asked questions
- What is the best free open-source communication app for Windows?
- ShareX is our first pick. Free, open-source screenshots, screen recording and GIFs for Windows. Yes. ShareX is free to use.
- Are these communication apps really free?
- Yes, every pick is free to start. ShareX is completely free. Mattermost, Zulip, Rocket.Chat and Element have free plans with paid upgrades.
- Do these open-source communication apps work on other platforms too?
- 4 picks of 5 also run elsewhere, including Mattermost (Web, macOS and Linux), Zulip (Web, macOS and Linux) and Rocket.Chat (Web, macOS and Linux).
- Which ones work offline on a Windows PC?
- ShareX is listed as working offline. The others need an internet connection for at least some features.
- How many free open-source communication apps for Windows are in the directory?
- 5 match right now, and all of them are on this page. New tools are added as they are checked.
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