Sozu website screenshot

Sozu

Sōzu is an open-source, fast and lightweight HTTP reverse proxy written in Rust, designed for high-performance traffic management in immutable infrastructure environments. It is configurable at runtime through a protobuf-based IPC protocol without requiring restarts, making it ideal for always-up deployments. Sōzu supports TLS termination, load balancing, and dynamic cluster configuration, and is developed by the sozu-proxy open-source organization on GitHub.

Sozu publishes 3 APIs on the APIs.io network. Tagged areas include Proxy, Reverse Proxy, Load Balancing, Rust, and Open Source.

The Sozu catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Sozu’s developer surface includes documentation, release notes, and 9 more developer resources.

🌐 Visit website 📡 Source on GitHub
39.7/100 thin ▬ flat Agent 3/100 human only Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1
AccessFreemium
3 APIs
ProxyReverse ProxyLoad BalancingRustOpen Source

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1
Composite quality — 39.7/100 · thin
Contract Quality 8.5 / 25
Developer Ergonomics 1.7 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 6.8 / 13
Governance 8.3 / 12
Discoverability 6.5 / 10
Agent readiness — 3/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/sozu: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 3

Individual APIs this provider publishes, each with its own machine-readable definition.

Sozu Command API

The Sozu Command API provides programmatic control of the Sōzu HTTP reverse proxy at runtime. External tools communicate with the Sozu main process through a secure Unix socket ...

Sozu ACME Integration

The Sozu ACME integration automates TLS certificate requests from Let's Encrypt and other ACME-enabled certificate authorities. Originally a standalone tool in the sozu-acme rep...

Sozu Command Futures API

The sozu-command-futures library provides a futures-based async Rust API for configuring the Sōzu HTTP reverse proxy programmatically. It wraps the low-level IPC protocol in an ...

Pricing Plans 1

Published pricing tiers and plan structures.

Sozu Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Sozu Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Sozu Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Sozu Context

8 classes · 16 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Sozu API Rules

5 rules · 4 warnings 1 info

SPECTRAL

JSON Schema 2

Standalone JSON Schema definitions for this provider's data models.

Sozu Cluster Configuration

6 properties

JSON SCHEMA

Sozu Frontend Configuration

8 properties

JSON SCHEMA

JSON Structure 1

JSON Structure definitions describing this provider's data shapes.

Sozu Configuration Structure

0 properties

JSON STRUCTURE

Examples 2

Example request and response payloads for these APIs.

Sozu Cluster Example

6 fields

EXAMPLE

Sozu Frontend Example

7 fields

EXAMPLE

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Sozu Domain Security

TLSv1.3 · DNSSEC

SECURITY

Resources

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

JSONLDContext
JSONLDContext
 Vocabulary
Vocabulary

Build 3

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 GitHubRepository
GitHubRepository
 Integration Tests
Integration Tests

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity

Operate 1

Status, limits, changes, and where to get help

ReleaseNotes
ReleaseNotes

Company 2

The organization behind the API

LinkedIn
LinkedIn
 Website
Website

Other 1

Properties that don't map to a standard resource type

Dashboard
Dashboard

Source (apis.yml)

apis.yml Raw ↑ 
aid: sozu
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/sozu.png
name: Sozu
description: Sōzu is an open-source, fast and lightweight HTTP reverse proxy written in Rust, designed for high-performance
  traffic management in immutable infrastructure environments. It is configurable at runtime through a protobuf-based IPC
  protocol without requiring restarts, making it ideal for always-up deployments. Sōzu supports TLS termination, load balancing,
  and dynamic cluster configuration, and is developed by the sozu-proxy open-source organization on GitHub.
url: https://raw.githubusercontent.com/api-evangelist/sozu/refs/heads/main/apis.yml
created: '2026-03-27'
modified: '2026-05-02'
specificationVersion: '0.19'
tags:
- Proxy
- Reverse Proxy
- Load Balancing
- Rust
- Open Source
apis:
- aid: sozu:sozu-command-api
  name: Sozu Command API
  description: The Sozu Command API provides programmatic control of the Sōzu HTTP reverse proxy at runtime. External tools
    communicate with the Sozu main process through a secure Unix socket using a protobuf-based binary protocol (IPC). The
    sozu-command-lib crate ships the protobuf schema, configuration parser, replicated state, channels, and file descriptor
    passing helpers. This enables dynamic cluster configuration, certificate management, and backend routing changes without
    restarts.
  humanURL: https://docs.sozu.io/
  baseURL: https://github.com/sozu-proxy/sozu
  tags:
  - Proxy
  - Command API
  - Protobuf
  - Runtime Configuration
  properties:
  - type: Documentation
    url: https://docs.sozu.io/
  - type: GitHub
    url: https://github.com/sozu-proxy/sozu
  - type: GettingStarted
    url: https://docs.sozu.io/getting-started/
  - type: Configuration
    url: https://github.com/sozu-proxy/sozu/blob/main/doc/configure.md
  - type: How To Use
    url: https://github.com/sozu-proxy/sozu/blob/main/doc/how_to_use.md
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/sozu/refs/heads/main/json-schema/sozu-cluster-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/sozu/refs/heads/main/json-schema/sozu-frontend-schema.json
- aid: sozu:sozu-acme-api
  name: Sozu ACME Integration
  description: The Sozu ACME integration automates TLS certificate requests from Let's Encrypt and other ACME-enabled certificate
    authorities. Originally a standalone tool in the sozu-acme repository, it has been integrated directly into the main Sōzu
    binary and is available as a command-line feature.
  humanURL: https://github.com/sozu-proxy/sozu-acme
  tags:
  - TLS
  - Certificates
  - ACME
  - Let's Encrypt
  properties:
  - type: GitHub
    url: https://github.com/sozu-proxy/sozu-acme
- aid: sozu:sozu-command-futures-api
  name: Sozu Command Futures API
  description: The sozu-command-futures library provides a futures-based async Rust API for configuring the Sōzu HTTP reverse
    proxy programmatically. It wraps the low-level IPC protocol in an ergonomic async interface for Rust applications.
  humanURL: https://github.com/sozu-proxy/sozu-command-futures
  tags:
  - Proxy
  - Rust
  - Async
  - Command API
  properties:
  - type: GitHub
    url: https://github.com/sozu-proxy/sozu-command-futures
common:
- type: DomainSecurity
  url: security/sozu-domain-security.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/sozu-limited
- type: Website
  url: https://www.sozu.io/
- type: Documentation
  url: https://docs.sozu.io/
- type: GitHubOrganization
  url: https://github.com/sozu-proxy
- type: GitHubRepository
  url: https://github.com/sozu-proxy/sozu
- type: ReleaseNotes
  url: https://github.com/sozu-proxy/sozu/releases
- type: Dashboard
  url: https://github.com/sozu-proxy/dashboard
- type: Integration Tests
  url: https://github.com/sozu-proxy/sozu-integration-tests
- type: JSONLDContext
  url: https://raw.githubusercontent.com/api-evangelist/sozu/refs/heads/main/json-ld/sozu-context.jsonld
- type: Vocabulary
  url: https://raw.githubusercontent.com/api-evangelist/sozu/refs/heads/main/vocabulary/sozu-vocabulary.yml
maintainers:
- FN: API Evangelist
  email: info@apievangelist.com