Resilience & Reliability

The gateway protects upstream backends through built-in traffic shaping, fault isolation, and connection recycling.

1. Circuit Breaker

Each upstream target is guarded by a circuit breaker state machine:

• CLOSED: Traffic flows normally. Error rates and timeout counters are monitored.
• OPEN: Upstream considered dead. Requests fail fast with HTTP 503 or return a cached fallback instantly without touching the backend network.
• HALF-OPEN: After a cooling interval, a canary probe is dispatched. If successful, the circuit closes; if it fails, it trips back to OPEN.

2. Load Balancing Strategies

Configure algorithms according to backend topology:

1. Round Robin: Sequential distribution across active instances.
2. Least Connections: Dispatches to the node with lowest active in-flight requests.
3. Weighted: Proportional routing based on node capacity ratings.
4. IP Hash: Deterministic client affinity based on caller IP.
5. Random: Low-overhead randomized distribution.

3. Intelligent Retries

• Method-Aware: Automatically retries idempotent verbs (GET, HEAD, OPTIONS, PUT) on connection resets (ECONNRESET, ETIMEDOUT).
• Exponential Backoff: Jittered delays avoid thundering herd storms on recovering services.

4. Rate Limiting Algorithms

Native token bucket and sliding window algorithms to throttle excessive client requests before they hit backend resources:

• Custom limiters by IP, client API token, or route path.
• Returns standard headers: X-RateLimit-Limit, X-RateLimit-Remaining, Retry-After.