Free picks · iPhone · Open source
Best free open-source communication apps for iPhone (2026)
Every pick is listed under Communication in our directory, runs on iPhone and iPad 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 iPhone.
Short answer
The best free open-source communication apps for iPhone are Mattermost, Zulip and Rocket.Chat, the top three of 9 matches in our directory. All 9 are tagged open source in our directory. 5 of the 9 picks are 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 9 picks, except the total.
- Matching tools
- 9
- Completely free
- 5
- Open source
- 9
- Work offline
- 0
- 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 | Mattermost | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Self-hosted, open-source team chat with a free edition for small teams. |
| 2 | 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. |
| 3 | 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. |
| 4 | Element | Free plan | Web, Windows, macOS, Linux, iOS, Android | Open source | Open-source, Matrix-based messaging you can self-host for free. |
| 5 | Farcaster | Free | Web, iOS, Android | Open source | The official app for the Farcaster decentralised social network, formerly Warpcast. |
| 6 | Jami | Free | Windows, macOS, Linux, iOS, Android | Open source | A free, private messaging and calling app that connects people directly, without a central server. |
| 7 | Mastodon | Free | Web, iOS, Android | Open source | A free, open-source social network made of independent servers. |
| 8 | Jitsi Meet | Free | Web, Android, iOS | Open source | Free, open-source video meetings with no account needed. |
| 9 | Lemmy | Free | Web, iOS, Android | Open source | A free, open-source forum network of linked communities. |
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 iPhone pick, rated 4.4/5. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web, Windows, macOS, Linux and 1 more platform. Its listing says it is privacy-focused (7 of 9 here). On our Mac list it is number 3. On the wider free iPhone list, open source or not, it is number 5.
Watch out for: You need to run and maintain your own server
Number 2 of 9 for iPhone, rated 4.5/5, the highest here. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web, macOS, Windows, Linux and 1 more platform. On our Mac list it is number 5. On the wider free iPhone list, open source or not, it is number 7.
Watch out for: Free cloud plan only searches the latest 10,000 messages
Number 3 of 9 for iPhone, rated 4.2/5. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web, Windows, macOS, Linux and 1 more platform. Its listing says it is privacy-focused (7 of 9 here). On our Mac list it is number 7. On the wider free iPhone list it ranks 13th, outside the top 10.
Watch out for: Self-managed only on the free plans, so you need technical setup
Number 4 of 9 for iPhone, rated 4.3/5. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web, Windows, macOS, Linux and 1 more platform. Its listing says it is privacy-focused (7 of 9 here). On our Mac list it is number 8. On the wider free iPhone list it ranks 14th, outside the top 10.
Watch out for: Self-hosting needs technical setup
Number 5 of 9 for iPhone, rated 4.1/5. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web and Android. It is not in the Mac top 10 (not listed for Mac). On the wider free iPhone list it ranks 16th, outside the top 10.
Watch out for: Can have a steeper learning curve for non-web3 users
Number 6 of 9 for iPhone, rated 4.3/5. Made mainly for communication, one of 8 such picks here. A mobile app that runs on iPhone and iPad, and also on Windows, macOS, Linux and Android. Its listing says it is privacy-focused (7 of 9 here) and is easy to pick up (4 of 9 here). It is not in the Mac top 10 (14th for Mac). On the wider free iPhone list it ranks 18th, outside the top 10.
Watch out for: Fewer of your contacts will already be on it
Number 7 of 9 for iPhone, rated 4.3/5. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web and Android. Its listing says it is privacy-focused (7 of 9 here) and is easy to pick up (4 of 9 here). It is not in the Mac top 10 (not listed for Mac). On the wider free iPhone list it ranks 19th, outside the top 10.
Watch out for: Choosing a server can confuse new users
Number 8 of 9 for iPhone, rated 4.3/5. Made mainly for meetings, it is the only pick here that covers communication as a second use. Runs on iPhone and iPad, and also on Web and Android. Its listing says it is privacy-focused (7 of 9 here) and is easy to pick up (4 of 9 here). It is not in the Mac top 10 (not listed for Mac). On the wider free iPhone list it ranks 20th, outside the top 10.
Watch out for: Call quality depends on the server you use
Number 9 of 9 for iPhone, rated 4.2/5. Made mainly for communication, one of 8 such picks here. Runs on iPhone and iPad, and also on Web and Android. Its listing says it is privacy-focused (7 of 9 here) and is easy to pick up (4 of 9 here). It is not in the Mac top 10 (not listed for Mac). On the wider free iPhone list it ranks 22nd, outside the top 10.
Watch out for: Smaller than the biggest forum sites
Running these on iPhone
Counted from each pick's listing type and platforms.
- By listing type, the 9 iPhone picks are 8 web apps (Mattermost, Zulip, Rocket.Chat, Element and 4 others) and 1 mobile app (Jami).
- 1 of 9 are apps you install on iPhone and iPad; the other 8 are web or cloud tools listed for iPhone.
- Every iPhone pick here also runs somewhere else. Element reaches furthest, on 5 other platforms besides iPhone.
- 5 of 9 also run on a Mac, so the same tool can follow you between iPhone and Mac; Farcaster, Mastodon, Jitsi Meet and Lemmy 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 Mac
4 of these 9 iPhone picks also make the Mac top 10. 5 are on this list only: Farcaster (not listed for Mac), Jami (14th for Mac), Mastodon (not listed for Mac), Jitsi Meet (not listed for Mac) and Lemmy (not listed for Mac). In their place the Mac list has Ferdium, Flameshot, Thunderbird, Mumble, Big Arrow on the Screen and Mailspring; none of them is listed for iPhone.
- Free communication apps for iPhone
Fine with closed source? The wider free iPhone list ranks 23 tools that run on iPhone and iPad, open source or not, led by Signal, Discord and Slack.
Frequently asked questions
- What is the best free open-source communication app for iPhone?
- Mattermost is our first pick. Self-hosted, open-source team chat with a free edition for small teams. Mattermost has a free plan, with paid plans that unlock more features or usage.
- Are these communication apps really free?
- Yes, every pick is free to start. Farcaster, Jami, Mastodon, Jitsi Meet and 1 other are 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?
- All 9 picks also run elsewhere, including Mattermost (Web, Windows and macOS), Zulip (Web, macOS and Windows) and Rocket.Chat (Web, Windows and macOS).
- Which ones work offline on iPhone and iPad?
- None of the picks here is listed as working offline, so expect to need an internet connection.
- Which are easiest for beginners?
- Jami, Mastodon and Jitsi Meet are rated beginner-friendly, along with 1 other pick. 5 picks take more time to learn.
- How many free open-source communication apps for iPhone are in the directory?
- 9 match right now, and all of them are on this page. New tools are added as they are checked.
Keep exploring
Wider lists
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- Free communication apps for Mac
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- Free communication apps for Linux
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