head to head · open source
Zen Browser vs extism
Zen Browser has 45,517 GitHub stars, 1,946 forks, 689 open issues and last shipped yesterday. extism has 5,823 stars, 167 forks, 54 open issues and last shipped 25 days ago. Zen Browser leads on adoption by 682% (45,517 vs 5,823 stars). Zen Browser is written in C++ under MPL-2.0; extism is written in Rust under BSD-3-Clause. Zen Browser has attracted 4% as many forks as stars, extism 3%. Zen Browser was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Zen Browser | extism | |
|---|---|---|
| GitHub stars | ★ 46K | ★ 5.8K |
| License | MPL-2.0 | BSD-3-Clause |
| Written in | C++ | Rust |
| Last push | 2026-11-02 | 2026-10-09 |
| Forks | ⑂ 1.9K | ⑂ 167 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Zen Browser if
- You weight community size — 46K stars and counting
- You want the MPL-2.0 license terms
- Your stack matches C++
- You value the larger contributor base for long-term maintenance
pick extism if
- You want the extism feature set and don't need the biggest community
- You prefer the BSD-3-Clause license terms
- Your stack matches Rust
- You evaluated both and extism fits your workflow better
About Zen Browser
Zen Browser Zen is a firefox based browser with the aim of pushing your productivity to a new level! Download • Website • Documentation • Release Notes Firefox Versions Release Is currently built using Firefox version 155.0.1 ! Twilight Is currently built using Firefox version RC 155.0.1 ! Contributing If you'd like to report a bug, please do so on our GitHub Issues page and for feature requests, you can use GitHub Discussions. Zen is an open source project, and we welcome contributions from the community! Please take a look at the contribution guidelines before getting started! Partners Thanks to all the…
read the full Zen Browser overview →
About extism
Overview Extism is a lightweight framework for building with WebAssembly (Wasm). It supports running Wasm code on servers, the edge, CLIs, IoT, browsers and everything in between. Extism is designed to be "universal" in that it supports a common interface, no matter where it runs. Note: One of the primary use cases for Extism is building extensible software & plugins . You want to be able to execute arbitrary, untrusted code from your users? Extism makes this safe and practical to do. Additionally, Extism adds some extra utilities on top of standard Wasm runtimes. For example, we support persistent memory/module…
read the full extism overview →
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Frequently asked questions
Is Zen Browser or extism more popular?
Zen Browser has 45,517 GitHub stars and extism has 5,823. Zen Browser has the larger community by that measure.
Are Zen Browser and extism free?
Both are open source. Zen Browser is licensed under MPL-2.0 and extism under BSD-3-Clause. Neither carries a licence fee.
What is the difference between Zen Browser and extism?
Zen Browser is written in C++ and extism in Rust. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Zen Browser or extism?
Choose Zen Browser if you want the larger community (45,517 stars) or its MPL-2.0 licence terms. Choose extism if its feature set, stack or BSD-3-Clause licence fits better. Both are self-hostable.