Sōzu review
A focused self-hosted proxy for Linux teams needing runtime changes and zero-downtime upgrades.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Sōzu is an open-source TCP and HTTP reverse proxy written in Rust, aimed at cloud providers, PaaS providers, and infrastructure teams managing frequently changing web workloads. It runs on Linux in self-hosted environments and is available from source, as Linux binaries, or through Docker. The feature set covers TLS termination, HTTP/1.1 and HTTP/2, WebSocket and secure WebSocket sessions, load balancing, per-IP rate limiting, logging, and metrics.
Its strongest fit is infrastructure that needs changes while traffic remains in service. Sōzu supports runtime configuration changes without reloads and zero-downtime upgrades, which suits teams operating dynamic web workloads. Load balancing includes multiple algorithms, while logs can be sent to stdout, files, TCP, UDP, or Unix sockets. StatsD and local metrics drains provide defined paths for operational visibility. The result is a focused proxy layer with useful traffic-management and observability capabilities without a separate paid tier in the published product details.
Sōzu is also a narrow operational choice. Deployment is self-managed, Linux is the listed platform, and configuration uses files, so teams must own the surrounding infrastructure and administration. Its AGPL-3.0-or-later license and open-source model suit organizations comfortable running software themselves. Choose Sōzu when runtime changes, protocol coverage, rate limiting, and zero-downtime operations matter most; choose a different option when you need a hosted reverse proxy or a broader managed platform experience.
Sōzu pros and cons
- Where it wins
- TCP and HTTP proxying with TLS, HTTP/2, and WebSockets
- Runtime configuration changes without reloads
- Free, open-source software with zero-downtime upgrades
- Where it doesn't
- Self-hosted deployment requires Linux infrastructure management
- Configuration is file-based rather than managed through a hosted console
- Designed for focused proxying rather than a broader application platform
Sōzu fact sheet, pricing and score →
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