Every team writes the same retry logic. The same circuit breaker boilerplate. The same mTLS handshake setup. The platform team changes the retry policy and now has to update 30 services. There’s a better way. The Sidecar Pattern A sidecar is a separate process running in the same pod as your service. It intercepts all network traffic in and out. Your service code is unchanged. The sidecar handles retries, timeouts, circuit breaking, load balancing, and observability.