Mastering API Conformance: Azure API Center, Spectral Linting, and Kiota Client Generation | Tech Playground

Welcome to this comprehensive session from Global Azure! Today we’re exploring the critical tools for achieving API maturity in modern organizations: Azure API Center, Spectral for API linting, and Kiota for client generation. This guide will help you understand when and how to implement these tools to build robust, governed API ecosystems.

Understanding API Maturity Models

Before diving into the tools, it’s crucial to understand where your organization stands in terms of API maturity. Organizations typically progress through several levels of API sophistication.

The Five Levels of API Maturity

Based on industry reports from Microsoft, IBM, Forrester, and Gartner, here are the common maturity levels:

1. Ad Hoc Level

No standardized API practices
Each project starts from scratch
Inconsistent documentation and governance
High development overhead

2. Repeatable Level

Basic API standards established
Some reusable components
Limited governance processes
Project-specific implementations

3. Managed Level 🎯

Centralized API inventory
Standardized development processes
Automated governance policies
Cross-team collaboration

4. Strategic Level 🎯

API-first architecture
Self-service developer experience
Comprehensive analytics and monitoring
Business-driven API strategy

5. Transformational Level

Innovation-focused API ecosystem
Market leadership through APIs
Advanced analytics and AI integration
Ecosystem-wide API monetization

Most organizations targeting efficiency and optimization operate at the Managed or Strategic levels, which is where the tools we’ll discuss today provide the most value.

The Tool Ecosystem Overview

Our journey covers three interconnected tools that work together to achieve API maturity:

🔍 Spectral: API linting and governance automation
⚡ Kiota: Multi-language API client generation
🏢 Azure API Center: Centralized API inventory and management

Spectral: Automating API Governance

Spectral is a JSON/YAML linter with out-of-the-box support for OpenAPI 3.x specifications. Instead of maintaining API manifestos in wikis or documentation, Spectral automates governance through enforceable rule sets.

Key Capabilities

Automated API Standards Enforcement: No more manual reviews
Customizable Rule Sets: JavaScript functions for complex validation
Integration Ready: Works with CI/CD pipelines
Multi-format Support: JSON and YAML API definitions

Creating Your First Spectral Rule Set

Let’s create a practical rule set for API governance:

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# global-azure.spectral.yml
extends: ["@stoplight/spectral-rulesets/dist/rulesets/oas"]

rules:
  api-description-required:
    description: "API info object must contain a description"
    message: "API description is required for documentation"
    severity: error
    given: "$.info"
    then:
      field: "description"
      function: "truthy"

  api-contact-required:
    description: "API info object should contain contact information"
    message: "Contact information helps with API ownership"
    severity: warn
    given: "$.info"
    then:
      field: "contact"
      function: "truthy"

  operation-description-required:
    description: "Each operation must contain a description"
    message: "Operations should be documented for better developer experience"
    severity: error
    given: "$.paths[*][*]"
    then:
      field: "description"
      function: "truthy"

  api-version-required:
    description: "API must have proper versioning"
    message: "Version information is required for API lifecycle management"
    severity: error
    given: "$.info"
    then:
      field: "version"
      function: "truthy"

Installing and Running Spectral

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# Install Spectral CLI
npm install -g @stoplight/spectral-cli

# Alternative: Using Yarn
yarn global add @stoplight/spectral-cli

# Run linting against your API definition
spectral lint weather-forecast.json --ruleset global-azure.spectral.yml

# Example output:
# weather-forecast.json
#   2:8  error  api-description-required  API description is required for documentation  info
#  12:10 error  api-contact-required      Contact information helps with API ownership   info.contact

Integration with CI/CD Pipelines

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# Azure DevOps Pipeline Example
- task: NodeTool@0
  displayName: 'Use Node.js'
  inputs:
    versionSpec: '16.x'

- script: |
    npm install -g @stoplight/spectral-cli
    spectral lint $(System.DefaultWorkingDirectory)/api-specs/*.json --ruleset .spectral.yml --format junit --output spectral-report.xml
  displayName: 'Run Spectral API Linting'

- task: PublishTestResults@2
  inputs:
    testResultsFormat: 'JUnit'
    testResultsFiles: 'spectral-report.xml'
    failTaskOnFailedTests: true
  displayName: 'Publish Spectral Results'

Advanced Rule Examples

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# Custom rule with JavaScript function
rules:
  consistent-response-schema:
    description: "All 200 responses should follow consistent schema"
    message: "Response schemas must be consistent across operations"
    severity: error
    given: "$.paths[*][*].responses.200.content.application/json.schema"
    then:
      function: "schema"
      functionOptions:
        schema:
          type: "object"
          required: ["data", "status", "message"]
          properties:
            data: true
            status:
              type: "integer"
            message:
              type: "string"

  security-scheme-required:
    description: "All operations must have security requirements"
    message: "Security is mandatory for all API operations"
    severity: error
    given: "$.paths[*][*]"
    then:
      field: "security"
      function: "truthy"

Kiota: Modern API Client Generation

Kiota is Microsoft’s open-source command-line tool for generating API clients from any OpenAPI-described API. It eliminates the need to manually create HTTP requests and provides strongly-typed clients across multiple languages.

Supported Languages

✅ .NET (C#)
✅ Java
✅ TypeScript/JavaScript
✅ Python
✅ Go
✅ PHP
✅ Ruby

Installation and Setup

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# Install Kiota CLI
dotnet tool install --global Microsoft.OpenApi.Kiota

# Verify installation
kiota --version

Generating .NET Clients

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# Generate a .NET client
kiota generate \
  --language CSharp \
  --class-name WeatherForecastClient \
  --namespace-name GlobalAzure.WeatherApi \
  --openapi weather-forecast.json \
  --output ./Generated/WeatherClient

# Required NuGet package for generated client
dotnet add package Microsoft.Kiota.Bundle

Example Generated Client Usage

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using GlobalAzure.WeatherApi;
using Microsoft.Kiota.Authentication.Azure;
using Microsoft.Kiota.Http.HttpClientLibrary;

// Configure authentication
var authProvider = new DefaultAzureCredential();
var requestAdapter = new HttpClientRequestAdapter(authProvider);

// Initialize the generated client
var weatherClient = new WeatherForecastClient(requestAdapter);

// Configure base URL and API key
requestAdapter.BaseUrl = "https://your-api-management.azure-api.net";
requestAdapter.RequestAdapter.SetHeader("Ocp-Apim-Subscription-Key", apiKey);

// Use the strongly-typed client
try
{
    var forecasts = await weatherClient.WeatherForecast.GetAsync();
    
    foreach (var forecast in forecasts.Value)
    {
        Console.WriteLine($"Date: {forecast.Date}");
        Console.WriteLine($"Temperature: {forecast.TemperatureC}°C / {forecast.TemperatureF}°F");
        Console.WriteLine($"Summary: {forecast.Summary}");
        Console.WriteLine("---");
    }
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

Multi-Language Client Generation

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# TypeScript client
kiota generate \
  --language TypeScript \
  --class-name WeatherApiClient \
  --openapi weather-forecast.json \
  --output ./clients/typescript

# Python client
kiota generate \
  --language Python \
  --class-name WeatherApiClient \
  --openapi weather-forecast.json \
  --output ./clients/python

# Java client
kiota generate \
  --language Java \
  --class-name WeatherApiClient \
  --namespace-name com.globalazure.weather \
  --openapi weather-forecast.json \
  --output ./clients/java

TypeScript Client Example

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import { WeatherApiClient } from './generated/weatherApiClient';
import { DefaultAzureCredential } from '@azure/identity';

// Initialize client with Azure authentication
const credential = new DefaultAzureCredential();
const client = new WeatherApiClient({
  baseUrl: 'https://your-api-management.azure-api.net',
  credential: credential
});

// Add subscription key header
client.requestAdapter.addRequestHeader('Ocp-Apim-Subscription-Key', process.env.API_KEY);

// Make typed requests
async function getWeatherForecast(): Promise<void> {
  try {
    const forecasts = await client.weatherForecast.get();
    
    forecasts?.forEach(forecast => {
      console.log(`${forecast.date}: ${forecast.temperatureC}°C - ${forecast.summary}`);
    });
  } catch (error) {
    console.error('Failed to fetch weather data:', error);
  }
}

await getWeatherForecast();

Azure API Center: Centralized API Catalog

Azure API Center provides a centralized inventory for all your APIs, regardless of where they’re hosted. It combines Spectral’s linting capabilities with Kiota’s client generation in a unified management experience.

Key Features

1. Centralized API Inventory

Track APIs across multiple environments
Support for Azure API Management integration
External API registration capabilities
Lifecycle management and versioning

2. Automated Governance

Built-in Spectral integration
Custom rule set deployment
Real-time compliance monitoring
Automated policy enforcement

3. Developer Experience

VS Code extension integration
One-click client generation
API discovery and documentation
Self-service capabilities

Setting Up Azure API Center

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# Create API Center instance
az apicenter create \
  --resource-group myResourceGroup \
  --service-name myApiCenter \
  --location westus2

# Connect to API Management
az apicenter import \
  --resource-group myResourceGroup \
  --service-name myApiCenter \
  --source-type "API Management" \
  --source-resource-id "/subscriptions/{subscription-id}/resourceGroups/{rg}/providers/Microsoft.ApiManagement/service/{apim-name}"

VS Code Integration

The Azure API Center extension provides seamless integration:

Install Extension: Search for “Azure API Center” in VS Code extensions
Connect to Azure: Sign in to your Azure subscription
Browse APIs: Explore your API inventory
Generate Clients: Right-click on any API to generate clients
Deploy Rules: Push Spectral rules directly to Azure

API Center Configuration Example

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{
  "apiCenter": {
    "resourceGroup": "api-governance-rg",
    "serviceName": "company-api-center",
    "defaultRuleSet": "corporate-standards.spectral.yml",
    "clientGeneration": {
      "defaultLanguage": "CSharp",
      "outputPath": "./generated-clients",
      "includeModels": true
    },
    "governance": {
      "enforceDescriptions": true,
      "requireContactInfo": true,
      "mandateVersioning": true,
      "securityRequired": true
    }
  }
}

Practical Implementation Workflow

1. Assessment Phase

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# Inventory existing APIs
az apicenter api list --resource-group myRG --service-name myApiCenter

# Run initial Spectral analysis
spectral lint **/*.json --ruleset corporate-standards.spectral.yml --format json > compliance-report.json

2. Standards Definition

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# corporate-standards.spectral.yml
extends: ["@stoplight/spectral-rulesets/dist/rulesets/oas"]

rules:
  # Security requirements
  security-definitions-required:
    description: "API must define security schemes"
    severity: error
    given: "$"
    then:
      field: "components.securitySchemes"
      function: "truthy"

  # Documentation standards
  comprehensive-descriptions:
    description: "All operations must have detailed descriptions"
    severity: error
    given: "$.paths[*][*]"
    then:
      field: "description"
      function: "length"
      functionOptions:
        min: 20

  # Response standards
  error-response-schema:
    description: "All error responses must follow standard schema"
    severity: error
    given: "$.paths[*][*].responses[4,5][0-9][0-9]"
    then:
      field: "content.application/json.schema"
      function: "truthy"

3. Automation Integration

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# GitHub Actions workflow
name: API Governance
on:
  push:
    paths: ['api-specs/**']
  pull_request:
    paths: ['api-specs/**']

jobs:
  validate-apis:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '18'
          
      - name: Install Spectral
        run: npm install -g @stoplight/spectral-cli
        
      - name: Run API Linting
        run: |
          spectral lint api-specs/*.json \
            --ruleset .spectral.yml \
            --format github-actions \
            --verbose

      - name: Generate Clients
        run: |
          dotnet tool install --global Microsoft.OpenApi.Kiota
          
          for spec in api-specs/*.json; do
            name=$(basename "$spec" .json)
            kiota generate \
              --language CSharp \
              --class-name "${name}Client" \
              --namespace-name Company.ApiClients \
              --openapi "$spec" \
              --output "clients/csharp/${name}"
          done

      - name: Deploy to API Center
        run: |
          az apicenter api import \
            --resource-group ${{ vars.RESOURCE_GROUP }} \
            --service-name ${{ vars.API_CENTER_NAME }} \
            --api-source api-specs/ \
            --format OpenAPI

Advanced Scenarios

Multi-Environment API Management

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# Development environment
az apicenter environment create \
  --resource-group myRG \
  --service-name myApiCenter \
  --environment-name "development" \
  --title "Development Environment" \
  --description "APIs in development phase"

# Production environment
az apicenter environment create \
  --resource-group myRG \
  --service-name myApiCenter \
  --environment-name "production" \
  --title "Production Environment" \
  --description "Live production APIs"

# Register API in specific environment
az apicenter api deployment create \
  --resource-group myRG \
  --service-name myApiCenter \
  --api-name weather-api \
  --deployment-name prod-deployment \
  --environment-name production \
  --server-url "https://api.company.com/weather"

Custom Spectral Functions

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// custom-functions.js
export default function validateApiKeyHeader(targetVal, _opts, context) {
  if (!targetVal || typeof targetVal !== 'object') {
    return [];
  }

  const hasApiKeyHeader = targetVal.parameters?.some(param => 
    param.name === 'X-API-Key' && 
    param.in === 'header' && 
    param.required === true
  );

  if (!hasApiKeyHeader) {
    return [
      {
        message: 'API operations should require X-API-Key header for authentication',
        path: [...context.path, 'parameters']
      }
    ];
  }

  return [];
}

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# Advanced rule set with custom function
extends: ["@stoplight/spectral-rulesets/dist/rulesets/oas"]
functions: ["./custom-functions.js"]

rules:
  api-key-required:
    description: "Operations should require API key authentication"
    message: "{{error}}"
    severity: error
    given: "$.paths[*][*]"
    then:
      function: "validateApiKeyHeader"

When to Implement Each Tool

Spectral Implementation Triggers

✅ Multiple development teams working on APIs
✅ Inconsistent API quality across projects
✅ Manual review processes that slow down delivery
✅ Compliance requirements for API standards
✅ Need for automated governance in CI/CD

Kiota Implementation Triggers

✅ Multiple client applications consuming your APIs
✅ Different programming languages in your ecosystem
✅ Manual HTTP client creation causing maintenance overhead
✅ Type safety requirements for API interactions
✅ Rapid prototyping needs for API consumers

API Center Implementation Triggers

✅ APIs scattered across different platforms and environments
✅ Lack of visibility into organizational API inventory
✅ Need for centralized governance across teams
✅ Developer self-service requirements
✅ API lifecycle management complexity

Performance and Cost Considerations

Spectral Performance Tips

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# Optimize large API definitions
spectral lint large-api.json --format json --quiet > results.json

# Parallel processing for multiple files
find api-specs/ -name "*.json" -print0 | xargs -0 -P 4 -I {} spectral lint {}

Kiota Generation Optimization

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# Generate only specific operations
kiota generate \
  --language CSharp \
  --include-path "/weather/*" \
  --exclude-path "/internal/*" \
  --openapi weather-api.json \
  --output ./client

API Center Cost Management

Resource Sizing: Start with basic tier for development
Regional Deployment: Choose regions close to your development teams
Monitoring: Set up alerts for API analysis job consumption
Cleanup: Regularly remove obsolete API versions

Troubleshooting Common Issues

Spectral Common Problems

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# Debug rule execution
spectral lint api.json --ruleset rules.yml --verbose

# Validate rule set syntax
spectral lint --ruleset rules.yml --help

# Fix YAML formatting issues
yamllint rules.yml

Kiota Generation Issues

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# Verify OpenAPI specification validity
kiota info --openapi api.json

# Debug authentication issues
kiota generate --language CSharp --openapi api.json --debug

# Handle circular references
kiota generate --language CSharp --openapi api.json --max-depth 3

API Center Integration Problems

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# Verify Azure CLI authentication
az account show

# Check API Center permissions
az role assignment list --assignee (az account show --query user.name -o tsv) --scope /subscriptions/{subscription-id}/resourceGroups/{rg}/providers/Microsoft.ApiCenter/services/{service-name}

# Validate API Management connection
az apicenter show --resource-group myRG --service-name myApiCenter

Best Practices and Recommendations

1. Start Small, Scale Gradually

Begin with basic Spectral rules for critical APIs
Implement Kiota for your most-used client languages first
Use API Center initially for visibility, then add governance

2. Establish Clear Governance

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# Governance rule priorities
rules:
  critical-security:
    severity: error
  documentation-standards:
    severity: warn
  best-practices:
    severity: info

3. Developer Experience Focus

Provide clear error messages in Spectral rules
Generate comprehensive client documentation
Offer self-service capabilities through API Center

4. Automation First

Integrate all tools into CI/CD pipelines
Automate client distribution through package managers
Set up automated compliance reporting

Conclusion

The combination of Spectral, Kiota, and Azure API Center provides a comprehensive solution for achieving API maturity in modern organizations. These tools work together to:

✅ Automate API Governance through enforceable rule sets
✅ Accelerate Development with generated, strongly-typed clients
✅ Centralize Management across distributed API ecosystems
✅ Improve Developer Experience through self-service capabilities
✅ Ensure Compliance with automated policy enforcement

Key Success Factors

Align with Business Goals: Implement these tools to solve specific organizational challenges
Start with Standards: Define clear API standards before implementing governance
Gradual Adoption: Begin with pilot projects and expand based on success
Developer Training: Ensure teams understand the tools and their benefits
Continuous Improvement: Regularly review and refine your governance policies

The journey to API maturity is iterative, but with these tools, organizations can achieve managed and strategic levels efficiently, enabling better collaboration, faster development, and more robust API ecosystems.

Resources

Have you implemented API governance in your organization? Share your experiences with Spectral, Kiota, or API Center in the comments below!

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