api.validate

api.validate

Overview

api.validate validates OpenAPI and AsyncAPI specifications against enterprise guidelines, with built-in support for Zalando RESTful API Guidelines.

Purpose

Ensure API specifications meet enterprise standards:

• Validate OpenAPI 3.x specifications
• Validate AsyncAPI 3.x specifications
• Check compliance with Zalando guidelines
• Detect common API design mistakes
• Provide actionable suggestions for fixes

Usage

Basic Usage

python skills/api.validate/api_validate.py <spec_path> [guideline_set] [options]

Parameters

Parameter	Required	Description	Default
spec_path	Yes	Path to API spec file	-
guideline_set	No	Guidelines to validate against	zalando
--strict	No	Warnings become errors	false
--format	No	Output format (json, human)	json

Guideline Sets

Guideline	Status	Description
zalando	✅ Supported	Zalando RESTful API Guidelines
google	🚧 Planned	Google API Design Guide
microsoft	🚧 Planned	Microsoft REST API Guidelines

Examples

Example 1: Validate OpenAPI Spec

python skills/api.validate/api_validate.py specs/user-service.openapi.yaml zalando

Output (JSON format):

{
  "status": "success",
  "data": {
    "valid": false,
    "errors": [
      {
        "rule_id": "MUST_001",
        "message": "Missing required field 'info.x-api-id'",
        "severity": "error",
        "path": "info.x-api-id",
        "suggestion": "Add a UUID to uniquely identify this API"
      }
    ],
    "warnings": [
      {
        "rule_id": "SHOULD_001",
        "message": "Missing 'info.contact'",
        "severity": "warning",
        "path": "info.contact"
      }
    ],
    "spec_path": "specs/user-service.openapi.yaml",
    "spec_type": "openapi",
    "guideline_set": "zalando"
  }
}

Example 2: Human-Readable Output

python skills/api.validate/api_validate.py \
  specs/user-service.openapi.yaml \
  zalando \
  --format=human

Output:

============================================================
API Validation Report
============================================================
Spec: specs/user-service.openapi.yaml
Type: OPENAPI
Guidelines: zalando
============================================================

❌ ERRORS (1):
  [MUST_001] Missing required field 'info.x-api-id'
    Path: info.x-api-id
    💡 Add a UUID to uniquely identify this API

⚠️  WARNINGS (1):
  [SHOULD_001] Missing 'info.contact'
    Path: info.contact
    💡 Add contact information

============================================================
❌ Validation FAILED
============================================================

Example 3: Strict Mode

python skills/api.validate/api_validate.py \
  specs/user-service.openapi.yaml \
  zalando \
  --strict

In strict mode, warnings are treated as errors. Use for CI/CD pipelines where you want zero tolerance for issues.

Example 4: Validate AsyncAPI Spec

python skills/api.validate/api_validate.py specs/user-events.asyncapi.yaml

Validation Rules

Zalando Guidelines (OpenAPI)

MUST Rules (Errors)

Rule	Description	Example Fix
MUST_001	Required x-api-id metadata	x-api-id: 'd0184f38-b98d-11e7-9c56-68f728c1ba70'
MUST_002	Required x-audience metadata	x-audience: 'company-internal'
MUST_003	Path naming conventions	Use lowercase kebab-case or snake_case
MUST_004	Property naming (snake_case)	userId → user_id
MUST_005	HTTP method usage	GET should not have requestBody

SHOULD Rules (Warnings)

Rule	Description	Example Fix
SHOULD_001	Contact information	Add info.contact with team details
SHOULD_002	POST returns 201	Add 201 response to POST operations
SHOULD_003	Document 400 errors	Add 400 Bad Request response
SHOULD_004	Document 500 errors	Add 500 Internal Error response
SHOULD_005	201 includes Location header	Add Location header to 201 responses
SHOULD_006	Problem schema for errors	Define RFC 7807 Problem schema
SHOULD_007	Error responses use application/problem+json	Use correct content type
SHOULD_008	X-Flow-ID header	Add request tracing header
SHOULD_009	Security schemes defined	Add authentication schemes

AsyncAPI Guidelines

Rule	Description
ASYNCAPI_001	Required info field
ASYNCAPI_002	Required channels field
ASYNCAPI_003	Version check (recommend 3.x)

Integration with Hooks

Automatic Validation on File Edit

# Create hook using hook.define
python skills/hook.define/hook_define.py \
  on_file_edit \
  "python betty/skills/api.validate/api_validate.py {file_path} zalando" \
  --pattern="*.openapi.yaml" \
  --blocking=true \
  --timeout=10000 \
  --description="Validate OpenAPI specs on edit"

Result: Every time you edit a *.openapi.yaml file, it's automatically validated. If validation fails, the edit is blocked.

Validation on Commit

python skills/hook.define/hook_define.py \
  on_commit \
  "python betty/skills/api.validate/api_validate.py {file_path} zalando --strict" \
  --pattern="specs/**/*.yaml" \
  --blocking=true \
  --description="Prevent commits with invalid specs"

Exit Codes

Code	Meaning
0	Validation passed (no errors)
1	Validation failed (has errors) or execution error

Common Validation Errors

Missing x-api-id

Error:

Missing required field 'info.x-api-id'

Fix:

info:
  title: My API
  version: 1.0.0
  x-api-id: d0184f38-b98d-11e7-9c56-68f728c1ba70  # Add this

Wrong Property Naming

Error:

Property 'userId' should use snake_case

Fix:

# Before
properties:
  userId:
    type: string

# After
properties:
  user_id:
    type: string

Missing Error Responses

Error:

GET operation should document 400 (Bad Request) response

Fix:

responses:
  '200':
    description: Success
  '400':  # Add this
    $ref: '#/components/responses/BadRequest'
  '500':  # Add this
    $ref: '#/components/responses/InternalError'

Wrong Content Type for Errors

Error:

Error response 400 should use 'application/problem+json'

Fix:

'400':
  description: Bad request
  content:
    application/problem+json:  # Not application/json
      schema:
        $ref: '#/components/schemas/Problem'

Use in Workflows

# workflows/api_validation_suite.yaml
steps:
  - skill: api.validate
    args:
      - "specs/user-service.openapi.yaml"
      - "zalando"
      - "--strict"
    required: true

Dependencies

• PyYAML: Required for YAML parsing

  pip install pyyaml
  

Files

Input

• *.openapi.yaml - OpenAPI 3.x specifications
• *.asyncapi.yaml - AsyncAPI 3.x specifications
• *.json - JSON format specifications

Output

• JSON validation report (stdout)
• Human-readable report (with --format=human)

See Also

• hook.define - Create validation hooks
• api.define - Create OpenAPI specs
• Betty Architecture - Five-layer model
• API-Driven Development - Complete guide
• Zalando API Guidelines
• RFC 7807 Problem Details

Version

0.1.0 - Initial implementation with Zalando guidelines support