Quantified backend system contributions Questions

Prepare 3-4 specific examples of backend systems you've architected or significantly improved. For each, quantify the impact: scalability improvements (e.g., 'handled 10x traffic growth'), performance wins (e.g., 'reduced p99 latency from 500ms to 50ms'), reliability improvements (e.g., 'achieved 99.99% uptime'), or business impact (e.g., 'unblocked 3 product teams'). Be ready to briefly describe the technical challenge and your role.