API Gateway Configuration and Patterns Cheat Sheet

Updated 2026-03-18

An API gateway serves as the single entry point for client requests in microservices and distributed architectures, managing routing, security, rate limiting, and protocol translation between clients and backend services. This centralized control plane enables consistent policy enforcement across all APIs while decoupling client interfaces from backend implementations. Key to modern cloud-native applications, effective gateway configuration balances security, performance, and developer experience — implementing patterns like request transformation, circuit breaking, and canary deployments ensures resilience while maintaining sub-100ms latency for critical traffic paths.

What This Cheat Sheet Covers

This topic spans 16 focused tables and 151 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.

Table 1: Routing PatternsTable 2: Authentication and AuthorizationTable 3: Rate Limiting and ThrottlingTable 4: Request and Response TransformationTable 5: Security Patterns and PoliciesTable 6: Caching StrategiesTable 7: API Composition and AggregationTable 8: Load Balancing and DistributionTable 9: Resilience and Fault ToleranceTable 10: API Versioning StrategiesTable 11: Monitoring and ObservabilityTable 12: Protocol and Integration TypesTable 13: Advanced Configuration FeaturesTable 14: Plugin and Middleware ArchitectureTable 15: Popular API Gateway SolutionsTable 16: Testing and Development Patterns

Table 1: Routing Patterns

Pattern	Example	Description
Path-based routing	`/api/v1/users` → Service A `/api/v1/orders` → Service B	Routes requests to different backend services based on the URL path, enabling logical API organization and service isolation.
Host-based routing	`api.example.com` → Production `staging.example.com` → Staging	• Routes traffic to different backends based on the hostname in the request • useful for multi-tenant or environment-specific routing.
Header-based routing	`X-API-Version: v2` → New Backend `X-API-Version: v1` → Legacy	• Directs requests to specific services based on HTTP header values • enables A/B testing and gradual migrations without URL changes.
Query parameter routing	`/search?region=us` → US Service `/search?region=eu` → EU Service	Routes based on query string parameters for region-specific or feature-flag-driven traffic distribution.
Method-based routing	`GET /users` → Read Service `POST /users` → Write Service	Maps HTTP methods to different backend integrations, supporting CQRS patterns and read/write separation.
Weighted routing	90% traffic → v1 10% traffic → v2	• Distributes traffic proportionally across multiple backends • essential for canary deployments and gradual rollouts.

Table 1: Routing Patterns

Pattern	Example	Description
Path-based routing	`/api/v1/users` → Service A `/api/v1/orders` → Service B	Routes requests to different backend services based on the URL path, enabling logical API organization and service isolation.
Host-based routing	`api.example.com` → Production `staging.example.com` → Staging	• Routes traffic to different backends based on the hostname in the request • useful for multi-tenant or environment-specific routing.
Header-based routing	`X-API-Version: v2` → New Backend `X-API-Version: v1` → Legacy	• Directs requests to specific services based on HTTP header values • enables A/B testing and gradual migrations without URL changes.
Query parameter routing	`/search?region=us` → US Service `/search?region=eu` → EU Service	Routes based on query string parameters for region-specific or feature-flag-driven traffic distribution.
Method-based routing	`GET /users` → Read Service `POST /users` → Write Service	Maps HTTP methods to different backend integrations, supporting CQRS patterns and read/write separation.
Weighted routing	90% traffic → v1 10% traffic → v2	• Distributes traffic proportionally across multiple backends • essential for canary deployments and gradual rollouts.