API Gateway Best Practices Interview Questions and Answers
Learn API Gateway best practices through 15 interview questions and answers. Understand security, routing, rate limiting, timeouts, retries, circuit breakers, observability, high availability, configuration management, performance, and production governance.
Introduction
An API Gateway is the primary entry point for web applications, mobile applications, partner systems, third-party consumers, and internal services.
Because nearly all external traffic passes through it, the gateway becomes one of the most critical components in a distributed system.
A poorly designed gateway can introduce:
- Security vulnerabilities
- High latency
- Routing failures
- Single points of failure
- Retry storms
- Inconsistent authentication
- Uncontrolled API traffic
- Difficult troubleshooting
- Configuration drift
- Production outages
A production-ready API Gateway should remain lightweight while consistently enforcing cross-cutting concerns such as authentication, authorization, routing, rate limiting, request validation, observability, and resilience.
This guide covers the 15 most important API Gateway best-practice interview questions with architecture diagrams, production examples, Spring Cloud Gateway configurations, common mistakes, and enterprise recommendations.
What You'll Learn
After completing this guide, you'll understand:
- API Gateway design principles
- Gateway responsibility boundaries
- Authentication and authorization
- Secure communication
- Routing best practices
- Rate limiting and quotas
- Timeouts and retries
- Circuit Breakers and fallbacks
- High availability
- Configuration management
- API versioning
- Observability
- Performance optimization
- Testing strategies
- Production governance
Production API Gateway Architecture
Web | Mobile | Partners
│
▼
Global Load Balancer
│
▼
Web Application Firewall
│
▼
Highly Available API Gateways
┌─────────┼─────────┐
▼ ▼ ▼
Gateway 1 Gateway 2 Gateway 3
│ │ │
└─────────┼─────────┘
▼
Authentication | Rate Limiting
│
Routing | Validation | Logging
│
Timeout | Circuit Breaker
│
▼
Backend Services
┌─────────────┼─────────────┐
▼ ▼ ▼
User Service Order Service Payment Service
│
▼
Logs | Metrics | Traces
│
▼
Prometheus | Grafana | OpenTelemetry
1. What are the Core Responsibilities of an API Gateway?
Answer
An API Gateway should handle cross-cutting concerns shared across multiple APIs.
Its main responsibilities include:
- Request routing
- Authentication
- Authorization
- Rate limiting
- Request validation
- TLS termination
- Header management
- Logging
- Metrics
- Distributed tracing
- Response transformation
- Resilience policies
Recommended Responsibility Boundary
API Gateway
↓
Cross-Cutting Technical Concerns
↓
Backend Services
↓
Business Logic and Domain Rules
What Should Remain in Backend Services?
Backend services should own:
- Business rules
- Domain validation
- Database transactions
- Workflow decisions
- Pricing calculations
- Payment processing logic
- Claims adjudication
- Order fulfillment
Interview Follow-Up
Should an API Gateway contain business logic?
No. The gateway should remain focused on traffic management and shared technical policies. Business logic in the gateway creates tight coupling and makes the gateway difficult to scale, test, and maintain.
2. Why Should an API Gateway Remain Lightweight?
Answer
Every request passing through the gateway adds processing work. Heavy custom logic can increase latency and reduce overall throughput.
The gateway should perform only necessary operations before forwarding the request.
Avoid
- Database queries for every request
- Complex business calculations
- Large payload processing
- Long-running operations
- Synchronous calls to many services
- Heavy response aggregation
- Excessive transformations
- Blocking operations in reactive gateways
Recommended Flow
Receive Request
↓
Authenticate
↓
Validate Basic Request Structure
↓
Apply Traffic Policies
↓
Route Request
↓
Return Response
Benefits
- Lower latency
- Better scalability
- Easier troubleshooting
- Higher throughput
- Reduced resource consumption
- Simpler deployments
3. How Should Authentication and Authorization Be Implemented?
Answer
Authentication should be centralized at the API Gateway, while important authorization decisions should also be enforced by backend services.
The gateway should validate:
- Token signature
- Token expiration
- Token issuer
- Token audience
- Required scopes
- Basic route-level roles
Backend services should still validate domain-specific permissions.
Security Flow
Client
↓
OAuth2 or OpenID Connect
↓
Identity Provider
↓
JWT Access Token
↓
API Gateway Validates Token
↓
Backend Validates Business Permission
Why Defense in Depth Matters
The gateway may confirm that a user has the claims.write scope.
The Claims Service must still verify whether that user is authorized to update the specific claim.
Spring Cloud Gateway Example
package com.codewithvenu.gateway.security;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.web.server.ServerHttpSecurity;
import org.springframework.security.web.server.SecurityWebFilterChain;
@Configuration
public class GatewaySecurityConfiguration {
@Bean
SecurityWebFilterChain securityWebFilterChain(
ServerHttpSecurity http) {
return http
.csrf(ServerHttpSecurity.CsrfSpec::disable)
.authorizeExchange(exchange -> exchange
.pathMatchers(
"/actuator/health",
"/public/**"
)
.permitAll()
.pathMatchers("/admin/**")
.hasRole("ADMIN")
.anyExchange()
.authenticated()
)
.oauth2ResourceServer(
ServerHttpSecurity.OAuth2ResourceServerSpec::jwt
)
.build();
}
}
4. What are API Gateway Transport Security Best Practices?
Answer
All external and internal gateway communication should use encrypted transport.
Recommended Practices
- Use HTTPS for all public APIs.
- Use modern TLS versions.
- Redirect or reject plain HTTP.
- Rotate certificates automatically.
- Use mTLS for sensitive partner APIs.
- Protect private keys using a secret manager.
- Validate backend certificates.
- Disable weak cipher suites.
- Monitor certificate expiration.
- Encrypt gateway-to-service communication.
Security Architecture
External Client
↓
HTTPS
↓
API Gateway
↓
mTLS or HTTPS
↓
Backend Service
Secret Storage Options
- HashiCorp Vault
- AWS Secrets Manager
- Azure Key Vault
- Google Secret Manager
- Kubernetes Secrets with encryption
- Enterprise certificate-management platforms
Common Mistake
Terminating TLS at the gateway and using unencrypted communication to backend services may expose traffic inside the network.
5. What are Routing Best Practices?
Answer
Routing rules should be simple, deterministic, documented, and centrally managed.
Recommended Practices
- Use clear route identifiers.
- Avoid overlapping path patterns.
- Prefer service discovery over hardcoded URLs.
- Use consistent path conventions.
- Keep route priorities explicit.
- Add default handling for unmatched routes.
- Validate configuration before deployment.
- Separate public and internal routes.
- Use host-based routing where appropriate.
- Monitor route-level failures.
Good Route Design
/api/v1/users/**
↓
USER-SERVICE
/api/v1/orders/**
↓
ORDER-SERVICE
/api/v1/payments/**
↓
PAYMENT-SERVICE
Poor Route Design
/api/**
/api/orders/**
/api/orders/payment/**
/**
Overlapping patterns can produce unexpected matches depending on route order and gateway behavior.
Spring Cloud Gateway Example
spring:
cloud:
gateway:
routes:
- id: user-service-route
uri: lb://USER-SERVICE
predicates:
- Path=/api/v1/users/**
- id: order-service-route
uri: lb://ORDER-SERVICE
predicates:
- Path=/api/v1/orders/**
- id: payment-service-route
uri: lb://PAYMENT-SERVICE
predicates:
- Path=/api/v1/payments/**
6. What are Rate Limiting and Quota Best Practices?
Answer
Rate limiting protects the platform from abuse and sudden traffic spikes. Quotas control API usage over longer periods.
Rate Limiting Examples
- 10 requests per second
- 100 requests per minute
- 1,000 requests per hour
Quota Examples
- 100,000 requests per month
- 1 million partner requests per billing cycle
Recommended Keys
Rate limits can be based on:
- User ID
- API key
- Client application
- JWT subject
- Partner organization
- IP address
- Subscription tier
- API route
Enterprise Model
Free Tier
100 Requests per Minute
↓
Premium Tier
1,000 Requests per Minute
↓
Partner Tier
Custom Contractual Limit
Best Practices
- Use distributed rate-limit storage.
- Apply stricter limits to login endpoints.
- Return HTTP 429.
- Include
Retry-Afterwhere appropriate. - Monitor rate-limit rejections.
- Avoid using IP address as the only identity.
- Allow controlled bursts.
- Define different limits by route and customer tier.
- Protect both gateway and backend capacity.
- Test limits with production-like concurrency.
7. How Should Timeouts Be Configured?
Answer
Every remote call should have a timeout.
Without timeouts, the gateway may wait indefinitely or for excessively long durations while holding network and processing resources.
Common Timeout Types
- Connection timeout
- Response timeout
- Read timeout
- Write timeout
- Idle timeout
- Overall request timeout
Timeout Hierarchy
Client Timeout
>
Gateway Timeout
>
Backend Internal Dependency Timeout
The client timeout should generally be longer than the gateway timeout so the gateway has enough time to return a controlled error.
Example
Client Timeout: 5 Seconds
Gateway Timeout: 3 Seconds
Backend Database Timeout: 2 Seconds
Spring Cloud Gateway Example
spring:
cloud:
gateway:
httpclient:
connect-timeout: 1000
response-timeout: 3s
Common Mistake
Setting the same 30-second timeout for every API ignores different business and performance requirements.
8. What are Retry Best Practices?
Answer
Retries should be used only for temporary failures and safe operations.
Examples of retryable conditions include:
- Connection reset
- Temporary service unavailability
- HTTP 502
- HTTP 503
- HTTP 504
- Transient network errors
Retry Flow
First Request Fails
↓
Wait with Backoff
↓
Retry Request
↓
Success or Final Failure
Best Practices
- Retry only idempotent operations.
- Limit retry attempts.
- Use exponential backoff.
- Add jitter.
- Respect the overall request deadline.
- Avoid retrying validation failures.
- Avoid retrying HTTP 401 or 403.
- Avoid retries across many system layers.
- Monitor retry counts.
- Use idempotency keys for critical operations.
Retry Storm
Gateway Retries 3 Times
↓
Service Retries 3 Times
↓
Database Client Retries 3 Times
↓
One Client Request Can Produce
Up to 27 Database Attempts
Spring Cloud Gateway Example
filters:
- name: Retry
args:
retries: 2
methods:
- GET
statuses:
- BAD_GATEWAY
- SERVICE_UNAVAILABLE
- GATEWAY_TIMEOUT
backoff:
firstBackoff: 100ms
maxBackoff: 500ms
factor: 2
basedOnPreviousValue: false
9. What are Circuit Breaker and Fallback Best Practices?
Answer
Circuit Breakers should protect the gateway from repeatedly calling unhealthy or slow downstream services.
Recommended Practices
- Use a separate circuit for each dependency.
- Configure minimum call counts.
- Monitor both failures and slow calls.
- Use realistic thresholds.
- Define an Open-state waiting period.
- Allow limited Half-Open calls.
- Return accurate fallback responses.
- Do not return HTTP 200 for failed operations.
- Combine Circuit Breakers with timeouts.
- Monitor state transitions.
Fallback Example
{
"status": 503,
"error": "PAYMENT_SERVICE_UNAVAILABLE",
"message": "Payment processing is temporarily unavailable.",
"traceId": "5f294e304f50c6d2"
}
Important Rule
Fallbacks must not hide business failures.
For example, a payment request must not return a cached or fake success response when the payment service is unavailable.
10. How Should an API Gateway Be Deployed for High Availability?
Answer
An API Gateway should never be deployed as a single instance in production.
Multiple stateless gateway instances should run behind a load balancer.
High-Availability Architecture
Global DNS
│
▼
Global Load Balancer
│
┌───────────┴───────────┐
▼ ▼
Region A Region B
│ │
Load Balancer Load Balancer
┌──┴──┐ ┌──┴──┐
▼ ▼ ▼ ▼
GW-A1 GW-A2 GW-B1 GW-B2
Best Practices
- Run at least two instances.
- Distribute instances across availability zones.
- Keep gateway instances stateless.
- Use readiness and liveness probes.
- Enable auto scaling.
- Test zone failure.
- Plan multi-region recovery where required.
- Replicate configuration securely.
- Avoid local-only session state.
- Monitor Control Plane and Data Plane health.
Kubernetes Example
apiVersion: apps/v1
kind: Deployment
metadata:
name: api-gateway
spec:
replicas: 3
selector:
matchLabels:
app: api-gateway
template:
metadata:
labels:
app: api-gateway
spec:
containers:
- name: api-gateway
image: company/api-gateway:1.0.0
ports:
- containerPort: 8080
readinessProbe:
httpGet:
path: /actuator/health/readiness
port: 8080
livenessProbe:
httpGet:
path: /actuator/health/liveness
port: 8080
11. How Should Gateway Configuration Be Managed?
Answer
Gateway configuration should be version-controlled, reviewed, tested, and promoted through automated deployment pipelines.
Recommended Workflow
Developer Changes Configuration
↓
Git Pull Request
↓
Review and Validation
↓
Automated Tests
↓
Deploy to Development
↓
Deploy to SIT or QA
↓
Deploy to Production
↓
Monitor and Roll Back if Required
Best Practices
- Store configuration in Git.
- Use pull-request reviews.
- Validate syntax automatically.
- Separate environment-specific values.
- Encrypt sensitive configuration.
- Maintain configuration history.
- Support rollback.
- Prevent manual production drift.
- Use GitOps for Kubernetes gateways.
- Audit configuration changes.
Avoid
- Editing production routes manually
- Hardcoding secrets
- Maintaining undocumented configurations
- Using different route logic in every environment
- Deploying unvalidated policy changes
12. What are API Versioning and Deprecation Best Practices?
Answer
API versioning allows APIs to evolve without immediately breaking existing consumers.
Common Strategies
- URI versioning:
/api/v1/orders - Header versioning
- Media-type versioning
- Query-parameter versioning
Recommended Lifecycle
Version 1 Active
↓
Version 2 Released
↓
Consumers Notified
↓
Migration Period
↓
Version 1 Deprecated
↓
Version 1 Removed
Best Practices
- Use a consistent versioning strategy.
- Avoid unnecessary versions.
- Maintain compatibility where possible.
- Publish migration documentation.
- Track usage by API version.
- Notify consumers before deprecation.
- Define sunset dates.
- Return deprecation headers.
- Avoid routing old and new versions to incompatible services accidentally.
- Test all supported versions.
Gateway Routing Example
spring:
cloud:
gateway:
routes:
- id: order-service-v1
uri: lb://ORDER-SERVICE-V1
predicates:
- Path=/api/v1/orders/**
- id: order-service-v2
uri: lb://ORDER-SERVICE-V2
predicates:
- Path=/api/v2/orders/**
13. What are API Gateway Observability Best Practices?
Answer
Every gateway request should be observable through structured logs, metrics, and distributed traces.
Three Pillars
Logs
+
Metrics
+
Traces
↓
Complete Request Visibility
Important Metrics
- Request count
- Requests per second
- P50 latency
- P95 latency
- P99 latency
- HTTP status distribution
- Authentication failures
- Rate-limit rejections
- Retry count
- Circuit Breaker state
- Backend response time
- Connection pool usage
- Active requests
- Route-level error rate
Structured Log Example
{
"timestamp": "2026-07-21T22:15:00Z",
"traceId": "a21f9b23d1994a2e",
"method": "POST",
"path": "/api/v1/payments",
"routeId": "payment-service-route",
"status": 503,
"durationMs": 214,
"clientId": "mobile-app",
"backend": "PAYMENT-SERVICE"
}
Recommended Tools
- OpenTelemetry
- Prometheus
- Grafana
- Splunk
- Elastic Stack
- Datadog
- Dynatrace
- New Relic
- Jaeger
- Zipkin
Important Security Rule
Never log:
- Passwords
- Access tokens
- Refresh tokens
- API keys
- Credit-card numbers
- Personal health information
- Sensitive personal data
14. What are API Gateway Performance Best Practices?
Answer
Gateway performance depends on routing complexity, security policies, transformations, logging, network design, and backend latency.
Recommended Practices
- Keep filters lightweight.
- Avoid blocking calls in reactive gateways.
- Reuse network connections.
- Tune connection pools.
- Minimize unnecessary transformations.
- Avoid logging complete payloads.
- Use compression selectively.
- Cache safe responses where appropriate.
- Scale horizontally.
- Monitor event-loop or thread utilization.
- Reduce unnecessary network hops.
- Keep authentication-key caches current.
- Load test with real policy chains.
- Monitor memory and garbage collection.
- Tune TLS and connection settings.
Performance Flow
Total API Latency
=
Network Latency
+
Gateway Processing
+
Authentication
+
Backend Latency
+
Response Processing
Common Mistake
Testing gateway performance with no authentication, no TLS, no logging, and a mock backend produces unrealistic results.
15. How Should API Gateways Be Tested and Governed?
Answer
Production readiness requires functional, security, performance, resilience, and operational testing.
Functional Testing
- Route matching
- Header handling
- Authentication
- Authorization
- Request transformation
- Response transformation
- Error handling
- API version routing
Security Testing
- Invalid JWT
- Expired JWT
- Incorrect audience
- Missing scopes
- Injection attacks
- Oversized payloads
- Invalid content type
- TLS configuration
- API-key leakage
- DDoS protection
Performance Testing
- Expected load
- Peak load
- Stress load
- Spike load
- Soak testing
- Large payloads
- High concurrency
- Authentication overhead
Resilience Testing
- Backend outage
- Slow backend
- Network latency
- Connection reset
- DNS failure
- Certificate failure
- Rate-limit datastore outage
- Control Plane failure
- Gateway instance failure
- Availability-zone failure
Governance Practices
- API design standards
- Naming conventions
- Security policy standards
- Versioning standards
- Error-response standards
- Documentation requirements
- Approval workflows
- Ownership assignment
- Deprecation policies
- Audit trails
Complete Spring Cloud Gateway Example
Maven Dependencies
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>
spring-boot-starter-oauth2-resource-server
</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>
spring-cloud-starter-circuitbreaker-reactor-resilience4j
</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis-reactive</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
</dependencies>
Production-Oriented Configuration
server:
port: 8080
spring:
application:
name: api-gateway
security:
oauth2:
resourceserver:
jwt:
issuer-uri: https://identity.company.com
cloud:
gateway:
httpclient:
connect-timeout: 1000
response-timeout: 3s
routes:
- id: order-service-route
uri: lb://ORDER-SERVICE
predicates:
- Path=/api/v1/orders/**
filters:
- name: RequestRateLimiter
args:
key-resolver: "#{@authenticatedUserKeyResolver}"
redis-rate-limiter.replenishRate: 20
redis-rate-limiter.burstCapacity: 40
- name: CircuitBreaker
args:
name: orderCircuitBreaker
fallbackUri: forward:/fallback/orders
- name: Retry
args:
retries: 2
methods:
- GET
statuses:
- BAD_GATEWAY
- SERVICE_UNAVAILABLE
- GATEWAY_TIMEOUT
resilience4j:
circuitbreaker:
instances:
orderCircuitBreaker:
sliding-window-type: COUNT_BASED
sliding-window-size: 20
minimum-number-of-calls: 10
failure-rate-threshold: 50
slow-call-rate-threshold: 50
slow-call-duration-threshold: 2s
wait-duration-in-open-state: 30s
permitted-number-of-calls-in-half-open-state: 5
management:
endpoints:
web:
exposure:
include:
- health
- metrics
- prometheus
endpoint:
health:
probes:
enabled: true
show-details: when-authorized
Key Resolver Example
package com.codewithvenu.gateway.ratelimit;
import java.security.Principal;
import org.springframework.cloud.gateway.filter.ratelimit.KeyResolver;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import reactor.core.publisher.Mono;
@Configuration
public class RateLimitConfiguration {
@Bean
KeyResolver authenticatedUserKeyResolver() {
return exchange -> exchange
.getPrincipal()
.map(Principal::getName)
.switchIfEmpty(Mono.just("anonymous"));
}
}
Fallback Controller
package com.codewithvenu.gateway.controller;
import java.time.Instant;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.UUID;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class GatewayFallbackController {
@GetMapping("/fallback/orders")
public ResponseEntity<Map<String, Object>> orderFallback() {
Map<String, Object> response = new LinkedHashMap<>();
response.put(
"status",
HttpStatus.SERVICE_UNAVAILABLE.value()
);
response.put(
"error",
"ORDER_SERVICE_UNAVAILABLE"
);
response.put(
"message",
"Order service is temporarily unavailable."
);
response.put(
"traceId",
UUID.randomUUID().toString()
);
response.put(
"timestamp",
Instant.now().toString()
);
return ResponseEntity
.status(HttpStatus.SERVICE_UNAVAILABLE)
.body(response);
}
}
API Gateway Production Checklist
| Area | Checklist |
|---|---|
| Architecture | Multiple stateless gateway instances |
| Security | OAuth2, JWT, TLS, mTLS where required |
| Routing | Clear, non-overlapping route definitions |
| Rate Limiting | Per-client and per-route limits |
| Timeouts | Connection and response deadlines |
| Retries | Limited to safe operations |
| Circuit Breakers | Separate circuit per dependency |
| Configuration | Git-managed and reviewed |
| Versioning | Documented lifecycle and deprecation |
| Logging | Structured and sanitized |
| Metrics | Route, status, latency, and failure metrics |
| Tracing | Trace context propagated end to end |
| Scaling | Horizontal auto scaling |
| Health | Readiness and liveness probes |
| Testing | Functional, security, load, and failure tests |
Common API Gateway Mistakes
| Mistake | Risk |
|---|---|
| Business logic in gateway | Tight coupling and latency |
| Single gateway instance | Single point of failure |
| No timeouts | Resource exhaustion |
| Excessive retries | Retry storms |
| Local rate-limit counters | Inconsistent distributed limits |
| Logging tokens | Security exposure |
| Hardcoded backend URLs | Poor scalability |
| Manual production changes | Configuration drift |
| HTTP 200 fallback | Misleading clients |
| No route-level metrics | Difficult troubleshooting |
| Shared circuit for all services | Incorrect failure isolation |
| Overlapping routes | Unexpected routing |
| No version strategy | Breaking API clients |
| Unencrypted backend traffic | Internal data exposure |
| No failure testing | Unknown production behavior |
API Gateway Best Practices Summary
| Practice | Recommendation |
|---|---|
| Responsibility | Keep gateway focused on cross-cutting concerns |
| Security | Validate identity at gateway and permissions in services |
| Transport | Use TLS externally and internally |
| Routing | Keep routes simple and deterministic |
| Rate Limiting | Use distributed, identity-based limits |
| Timeouts | Define strict deadlines for all remote calls |
| Retries | Retry only safe transient failures |
| Circuit Breakers | Fail fast when dependencies are unhealthy |
| Availability | Run multiple stateless instances |
| Configuration | Use Git, automation, validation, and rollback |
| Versioning | Maintain a documented deprecation lifecycle |
| Observability | Collect logs, metrics, and traces |
| Performance | Minimize processing and blocking operations |
| Testing | Test realistic traffic and failure conditions |
| Governance | Enforce organization-wide API standards |
Interview Tips
- Start by explaining that the gateway should remain lightweight.
- Clearly separate cross-cutting concerns from business logic.
- Explain authentication at the gateway and authorization in depth.
- Discuss TLS and mTLS.
- Explain deterministic routing.
- Compare rate limiting and quotas.
- Mention connection and response timeouts.
- Explain why retries require idempotency.
- Discuss Circuit Breakers and accurate fallback responses.
- Explain high availability across zones.
- Describe Git-based configuration management.
- Discuss API versioning and deprecation.
- Mention logs, metrics, traces, and trace IDs.
- Explain production-like performance testing.
- Include security, resilience, and governance testing.
Key Takeaways
- An API Gateway should remain lightweight and focus on shared technical concerns.
- Business rules and domain logic should remain inside backend services.
- Authentication should be centralized, but backend services must continue enforcing domain authorization.
- HTTPS, certificate rotation, and encrypted backend communication are essential.
- Routing rules should be deterministic, documented, and free from unnecessary overlap.
- Distributed rate limiting protects both the gateway and backend services.
- Every remote call requires appropriate connection and response timeouts.
- Retries should be limited, delayed, and restricted to safe operations.
- Circuit Breakers prevent cascading failures and support fail-fast behavior.
- Production gateways require multiple stateless instances across failure zones.
- Gateway configuration should be version-controlled and promoted through automated pipelines.
- API versioning must include consumer communication and deprecation planning.
- Structured logs, metrics, and distributed traces are required for troubleshooting.
- Performance tests should include real authentication, TLS, logging, payloads, and backend behavior.
- Gateway production readiness requires functional, security, resilience, operational, and governance testing.