Zally

Zally is an open source API linter from Zalando that validates OpenAPI 2 and 3 specifications against configurable rule sets for API design consistency. It exposes a REST API, command-line interface, and web UI for checking API designs against Zalando's RESTful API Guidelines or custom rule sets.

Zally publishes 3 APIs on the APIs.io network: Api Violations API, Review Statistics API, and Supported Rules API. Tagged areas include API Design, API Linting, API Quality, Open Source, and OpenAPI.

The Zally catalog on APIs.io includes 1 JSON-LD context and 2 Spectral governance rulesets.

Zally’s developer surface includes authentication, documentation, changelog, CLI, and 12 more developer resources.

🌐 Visit website 📡 Source on GitHub

57.0/100 strong ▬ flat Agent 44/100 agent ready Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1

AccessFreemiumSelf serve⚡ Free to try

3 APIs 6 Features 4 Use Cases

API DesignAPI LintingAPI QualityOpen SourceOpenAPIZalando

Kin Score

Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1

Composite quality — 57.0/100 · strong

Contract Quality 19.2 / 25

Developer Ergonomics 7.4 / 20

Commercial Clarity 7.9 / 20

Operational Transparency 6.8 / 13

Governance 8.3 / 12

Discoverability 7.4 / 10

Agent readiness — 44/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 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/zally: 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.

Rate Limits 1

Documented rate limits and quota policies.

Zally Rate Limits

5 limits

RATE LIMITS

FinOps 1

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

Zally Finops

FINOPS

Features 6

Notable capabilities this provider offers.

API Linting

Validate OpenAPI 2/3 specifications against rule sets to enforce design consistency.

Configurable Rules

Customize default Zalando RESTful API Guidelines rules or define custom rule sets.

Multiple Interfaces

REST API for programmatic access, CLI for local checking, and Web UI for visual review.

Ignore Extension

Use x-zally-ignore extension in specs to selectively bypass rules.

Rule Severity Levels

Rules categorized as MUST, SHOULD, COULD, MAY, and HINT for graduated enforcement.

Linting Statistics

Track linting requests and aggregate review statistics over time.

JSON Schema 8

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

Scroll for all 8

Examples 7

Example request and response payloads for these APIs.

Scroll for all 7

Use Cases 4

What developers build with this provider.

API Design Review

Review OpenAPI specs in pull requests to enforce design standards before merge.

API Governance

Enforce organizational API guidelines across teams via shared rule sets.

API Quality Gate

Block API releases that violate critical MUST rules in CI/CD pipelines.

Style Guide Enforcement

Encode an API style guide as executable rules and apply consistently.

Integrations 3

Pre-built integrations with other platforms and tools.

GitHub Actions

Run Zally linting in GitHub Actions workflows on PRs.

Spectral

Translate Zally rule sets to Spectral rulesets for OpenAPI 3 alignment.

Zalando RESTful API Guidelines

Default rule set ships with rules from Zalando's public API guidelines.

Resources

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

Specification

Specification

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Design & Contract 2

Pagination, idempotency, versioning, errors, and events

SpectralRules

SpectralRules

Vocabulary

Vocabulary

Build 5

SDKs, sample code, and the tooling you integrate with

PostmanWorkspace

PostmanWorkspace

GitHubRepository

GitHubRepository

GitHubOrganization

GitHubOrganization

CLI

CLI

SDKs

SDKs

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

Issues

Issues

ChangeLog

ChangeLog

Commercial 1

Pricing, plans, and the legal terms of use

License

License

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: zally
name: Zally
description: Zally is an open source API linter from Zalando that validates OpenAPI 2 and 3 specifications against configurable
  rule sets for API design consistency. It exposes a REST API, command-line interface, and web UI for checking API designs
  against Zalando's RESTful API Guidelines or custom rule sets.
type: Index
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/zally.png
tags:
- API Design
- API Linting
- API Quality
- Open Source
- OpenAPI
- Zalando
url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/apis.yml
created: '2026-03-25'
modified: '2026-05-19'
specificationVersion: '0.19'
apis:
- aid: zally:zally-api-violations-api
  name: Zally Api Violations API
  description: The Api Violations API from Zally — 2 operation(s) for api violations.
  humanURL: https://opensource.zalando.com/zally/
  baseURL: https://zally.on.inter.net
  tags:
  - Api Violations
  properties:
  - type: OpenAPI
    url: openapi/zally-api-violations-api-openapi.yml
  - type: Documentation
    url: https://opensource.zalando.com/zally/
  - type: APIReference
    url: https://github.com/zalando/zally/blob/main/server/zally-server/src/main/resources/api/zally-api.yaml
  - type: Authentication
    url: https://github.com/zalando/zally/tree/main/server#authentication
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-schema/
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-structure/
  - type: JSONLD
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-ld/zally-context.jsonld
  - type: Examples
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/examples/
- aid: zally:zally-review-statistics-api
  name: Zally Review Statistics API
  description: The Review Statistics API from Zally — 1 operation(s) for review statistics.
  humanURL: https://opensource.zalando.com/zally/
  baseURL: https://zally.on.inter.net
  tags:
  - Review Statistics
  properties:
  - type: OpenAPI
    url: openapi/zally-review-statistics-api-openapi.yml
  - type: Documentation
    url: https://opensource.zalando.com/zally/
  - type: APIReference
    url: https://github.com/zalando/zally/blob/main/server/zally-server/src/main/resources/api/zally-api.yaml
  - type: Authentication
    url: https://github.com/zalando/zally/tree/main/server#authentication
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-schema/
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-structure/
  - type: JSONLD
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-ld/zally-context.jsonld
  - type: Examples
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/examples/
- aid: zally:zally-supported-rules-api
  name: Zally Supported Rules API
  description: The Supported Rules API from Zally — 1 operation(s) for supported rules.
  humanURL: https://opensource.zalando.com/zally/
  baseURL: https://zally.on.inter.net
  tags:
  - Supported Rules
  properties:
  - type: OpenAPI
    url: openapi/zally-supported-rules-api-openapi.yml
  - type: Documentation
    url: https://opensource.zalando.com/zally/
  - type: APIReference
    url: https://github.com/zalando/zally/blob/main/server/zally-server/src/main/resources/api/zally-api.yaml
  - type: Authentication
    url: https://github.com/zalando/zally/tree/main/server#authentication
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-schema/
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-structure/
  - type: JSONLD
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/json-ld/zally-context.jsonld
  - type: Examples
    url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/examples/
common:
- type: PostmanWorkspace
  url: https://www.postman.com/kinlaneapi/zally/overview
- type: AgenticAccess
  url: agentic-access/zally-agentic-access.yml
- type: DomainSecurity
  url: security/zally-domain-security.yml
- type: Authentication
  url: authentication/zally-authentication.yml
- type: Website
  url: https://opensource.zalando.com/zally/
  name: Zally Project Website
- type: Documentation
  url: https://github.com/zalando/zally#readme
  name: Zally README
- type: GitHubRepository
  url: https://github.com/zalando/zally
  name: Zalando Zally Repository
- type: GitHubOrganization
  url: https://github.com/zalando
  name: Zalando GitHub Organization
- type: License
  url: https://github.com/zalando/zally/blob/main/LICENSE
  name: MIT License
- type: Issues
  url: https://github.com/zalando/zally/issues
  name: GitHub Issues
- type: ChangeLog
  url: https://github.com/zalando/zally/releases
  name: Releases
- type: CLI
  url: https://github.com/zalando/zally/tree/main/cli
  name: Zally CLI
- type: SDKs
  url: https://github.com/zalando/zally/tree/main/web-ui
  name: Zally Web UI
- type: Specification
  url: https://opensource.zalando.com/restful-api-guidelines/
  name: Zalando RESTful API Guidelines
- type: SpectralRules
  url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/rules/zally-rules.yml
  name: Zally Spectral Ruleset
- type: Vocabulary
  url: https://raw.githubusercontent.com/api-evangelist/zally/refs/heads/main/vocabulary/zally-vocabulary.yml
  name: Zally Vocabulary
- data:
  - name: API Linting
    description: Validate OpenAPI 2/3 specifications against rule sets to enforce design consistency.
  - name: Configurable Rules
    description: Customize default Zalando RESTful API Guidelines rules or define custom rule sets.
  - name: Multiple Interfaces
    description: REST API for programmatic access, CLI for local checking, and Web UI for visual review.
  - name: Ignore Extension
    description: Use x-zally-ignore extension in specs to selectively bypass rules.
  - name: Rule Severity Levels
    description: Rules categorized as MUST, SHOULD, COULD, MAY, and HINT for graduated enforcement.
  - name: Linting Statistics
    description: Track linting requests and aggregate review statistics over time.
  name: Features
  type: Features
- data:
  - name: API Design Review
    description: Review OpenAPI specs in pull requests to enforce design standards before merge.
  - name: API Governance
    description: Enforce organizational API guidelines across teams via shared rule sets.
  - name: API Quality Gate
    description: Block API releases that violate critical MUST rules in CI/CD pipelines.
  - name: Style Guide Enforcement
    description: Encode an API style guide as executable rules and apply consistently.
  name: UseCases
  type: UseCases
- data:
  - name: GitHub Actions
    description: Run Zally linting in GitHub Actions workflows on PRs.
  - name: Spectral
    description: Translate Zally rule sets to Spectral rulesets for OpenAPI 3 alignment.
  - name: Zalando RESTful API Guidelines
    description: Default rule set ships with rules from Zalando's public API guidelines.
  name: Integrations
  type: Integrations
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com