caddy-l4 vs Sozu
A side-by-side comparison of two self-hosted reverse proxy & gateways options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | caddy-l4 | Sozu |
|---|---|---|
| Deploy effort | Read-the-docs project | Under-an-hour setup |
| Health score | 85 · Excellent | 88 · Excellent |
| Category | Reverse Proxy & Gateways | Reverse Proxy & Gateways |
| License | Apache-2.0 | AGPL-3.0 |
| Language | Go | Rust |
| Setup difficulty | Medium | Hard |
| Min. RAM | 64 MB | 128 MB |
| Deployment | binary, source | docker, binary |
| GitHub stars | ★ 1,780 | ★ 3,734 |
| First released | 2020 | 2016 |
| Replaces | HAProxy | HAProxy, Nginx |
What are caddy-l4 and Sozu?
caddy-l4
Caddy-L4 is an experimental application-layer-aware Layer 4 proxy app for the Caddy server, enabling TCP and UDP routing alongside Caddy's HTTP features. It allows protocol multiplexing on a single port.
- TCP and UDP proxying
- Protocol multiplexing
- Caddy integration
- Connection matchers
Sozu
Sozu is an open-source HTTP reverse proxy written in Rust that can be reconfigured at runtime without dropping connections. It is built for safety and zero-downtime configuration changes.
- Hot configuration reload
- Memory-safe Rust core
- Zero-downtime changes
- Runtime control API
caddy-l4 vs Sozu: key differences
Caddy-l4 is written in Go, while Sozu is built with Rust. Licensing differs — Apache-2.0 for caddy-l4 versus AGPL-3.0 for Sozu. Caddy-l4 is the lighter option, starting around 64 MB of RAM against 128 MB for Sozu. Sozu is the more established project (first released 2016), while caddy-l4 arrived in 2020. Sozu has the considerably larger community, at 3,734 GitHub stars versus 1,780. Sozu lists first-class Docker deployment; caddy-l4 does not.
Why pick each one
Choose caddy-l4 if…
- Extends Caddy nicely
- Port multiplexing
Watch out for
- Marked experimental
- Requires Caddy knowledge
Choose Sozu if…
- Released under the AGPL-3.0 license
- First-class Docker support for quick deployment
- Active community (3.7k GitHub stars)
- Written in Rust
Frequently asked questions
Is caddy-l4 or Sozu better?
Neither is universally better. Sozu has the larger community, while caddy-l4 is simpler to set up (medium difficulty). Choose based on the comparison table above and your own setup.
Are caddy-l4 and Sozu free and open-source?
Yes. caddy-l4 is licensed under Apache-2.0 and Sozu under AGPL-3.0. Both can be self-hosted at no software cost.
Can I run caddy-l4 and Sozu with Docker?
caddy-l4: check the project docs for container support. Sozu: yes.
Which is lighter on resources, caddy-l4 or Sozu?
caddy-l4 has the smaller minimum footprint at 64 MB of RAM, compared to about 128 MB for Sozu. Real-world usage depends on library size, user count, and enabled features.