The API Gateway Handbook

Why This Book?

API Gateways are critical components in modern software architecture. Whether you're working with microservices, securing APIs, or managing traffic at scale, this book offers a hands-on guide built on years of practical experience and open source development.

What’s Inside

• Understanding API Gateways
  What is an API Gateway? Roles and responsibilities, how they differ from HTTP proxies and WAFs, and the main types of gateways.
• How an API Gateway works?
  Routing, message flow, plugins, expression languages
• Deployment Strategies
  Stand-alone vs. containerized, placement in the DMZ, and clustering.
• Installation and ApiOps
  Setting up infrastructure, pipelines, and Git-based workflows.
• OpenAPI
  Configure gateways directly from OpenAPI documents and enable validation.
• Orchestration
  Combine calls, aggregate responses, and handle errors gracefully.
• API Security
  Authentication, TLS, attack protection for JSON and GraphQL, API keys, tokens, OAuth 2, OIDC, and JWT.
• CORS
  Using APIs with CORS, origins and preflight configuration
• Message Validation
  Validate JSON, XML, and OpenAPI payloads.
• Traffic Control
  Apply routing rules, rate limits, quotas, and throttling.
• Load Balancing
  Choose algorithms, manage clusters, health checks, availability, and failover.
• Performance
  Latency and bandwidth. How fast is an API Gateway?

• Membrane Installation and Configuration
  First steps, Getting started
• Routing Traffic
  Routing based on path, method, host, dynamic with if, ...
• Internals
  Exchange and message, properties
• OpenAPI
  Configuration, validation, rewriting
• Transformation
  JSON and XML mapping, field masking, schema evolution, versioning
• API Security
  SSL/TLS, validation of JSON Tokens, OAuth2, OpenID Connect
• Legacy Integration
  Mocking a Web Service, routing SOAP, WSDL support, XML to JSON transformation
• Observability
  Structured logs, tracing, metrics, dashboards

Who Should Read It?

Software developers, architects, DevOps engineers, and product managers working with APIs who want to understand, setup, and operate API Gateways effectively.