Caddy 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.
Caddy
Fast, multi-platform web server with automatic HTTPS
VS
Sozu
Hot-reconfigurable HTTP reverse proxy in Rust
| Feature | Caddy | Sozu |
|---|---|---|
| Deploy effort | ≈5-minute setup | Under-an-hour setup |
| Health score | 99 · Excellent | 88 · Excellent |
| Category | Reverse Proxy & Gateways | Reverse Proxy & Gateways |
| License | Apache-2.0 | AGPL-3.0 |
| Language | Go | Rust |
| Setup difficulty | Easy | Hard |
| Min. RAM | 64 MB | 128 MB |
| Deployment | docker, binary, bare-metal | docker, binary |
| GitHub stars | ★ 76,036 | ★ 3,734 |
| First released | 2015 | 2016 |
| Replaces | Nginx, Apache | HAProxy, Nginx |
What are Caddy and Sozu?
Caddy
Caddy is a powerful, extensible web server and reverse proxy written in Go that provides automatic HTTPS out of the box. Its simple configuration makes it popular for self-hosting.
- Automatic HTTPS by default
- Simple Caddyfile config
- Single binary
- Plugin ecosystem
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 vs Sozu: key differences
Caddy is written in Go, while Sozu is built with Rust. Licensing differs — Apache-2.0 for Caddy versus AGPL-3.0 for Sozu. Caddy is the lighter option, starting around 64 MB of RAM against 128 MB for Sozu. Caddy has the considerably larger community, at 76,036 GitHub stars versus 3,734.
Why pick each one
Choose Caddy if…
- Zero-config TLS
- Easy to learn
Watch out for
- Fewer tuning knobs than Nginx
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 or Sozu better?
Caddy is the stronger all-round pick: it has both the larger community and the simpler easy setup. Consider Sozu if its specific feature set fits your needs better.
Are Caddy and Sozu free and open-source?
Yes. Caddy 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 and Sozu with Docker?
Caddy: yes. Sozu: yes.
Which is lighter on resources, Caddy or Sozu?
Caddy 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.