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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.

human only

Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.

Kin Score

API Evangelist profiles Sozu the way a machine reads it — 14 machine-readable artifacts across 3 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.

Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Sozu scores 45.5/100 (developing), with a separate agent-readiness read of 7/100 (human only). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.

Kin Score

This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 45.5/100 · developing
Contract Quality 9.9 / 25
Developer Ergonomics 1.7 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 6.8 / 13
Governance 10.4 / 12
Discoverability 8.8 / 10
Agent readiness — 7/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
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

How we profile Sozu

Each block below is one kind of artifact we hold for Sozu. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.

APIs 3

Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.

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

Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.

Published pricing tiers and plan structures.

Sozu Plans Pricing

3 plans

PLANS

Rate Limits 1

Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.

Documented rate limits and quota policies.

Sozu Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.

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

Sozu Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.

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

Sozu Context

8 classes · 16 properties

JSON-LD

Spectral Rules 1

Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.

Sozu API Rules

5 rules · 4 warnings

SPECTRAL

JSON Schema 2

Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.

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 captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.

JSON Structure definitions describing this provider's data shapes.

Sozu Configuration Structure

0 properties

JSON STRUCTURE

Examples 2

Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.

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 — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.

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

Sozu Domain Security

TLSv1.3 · DNSSEC

SECURITY

Resources

Every other property we hold for Sozu — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.

Documentation 1

Reference material describing how the API behaves

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

Access & Security 1

Authentication, authorization, and security posture

Operate 1

Status, limits, changes, and where to get help

Company 2

The organization behind the API

Other 1

Properties that don't map to a standard resource type

← All providers · Data indexed from github.com/api-evangelist/sozu · machine-readable index on apis.io