System Design Check List

1. ๐ŸŒ User Assumptions

  • Total Users:
  • Daily Active Users (DAU):
  • Peak Concurrent Users:
  • Average Session Duration:
  • Actions per User per Day:

2. ๐Ÿ” Traffic Estimation

  • Requests per User per Day:
  • Total Daily Requests:
  • Average RPS:
  • Peak RPS Estimate:
  • Avg Payload Size (KB):
  • Bandwidth In/Out per Day:

3. ๐Ÿ’พ Storage Estimation

  • Data per User per Day:
  • Daily Total Data Written:
  • Retention Period:
  • Total Storage Needed:
  • Index Overhead Estimate:
  • Replication Factor:
  • Final Storage with Replication:

4. ๐Ÿ“š Read/Write Patterns

  • Read QPS:
  • Write QPS:
  • Read:Write Ratio:
  • Type of Reads:
  • Write Frequency / Criticality:

5. โš™๏ธ Backend Compute Estimation

  • Estimated CPU per Request:
  • Memory per Request:
  • # of Instances Needed:
  • Batch/Async Job Load:
  • Throughput of Worker Jobs:

6. ๐Ÿ•“ Latency Targets

  • P95 Target Latency:
  • P99 Target Latency:
  • Timeout Budgets:
  • Cold Start/Init Time:

7. ๐Ÿ“ฆ Caching Strategy

  • Cache Types:
  • Avg Cache Hit Ratio:
  • Origin Load (uncached reqs):
  • Eviction Policy / TTLs:

8. ๐Ÿ” Security and Limits

  • Auth Type:
  • Rate Limit per User/IP:
  • Token Size and Auth Storage:
  • Data Sensitivity:

9. ๐Ÿ”„ Replication & Availability

  • Replication Strategy:
  • Failover Time Goal:
  • Consistency Model:
  • Expected Downtime Tolerance:

10. ๐Ÿ“Š Monitoring & Metrics

  • Throughput per Component:
  • Error Rate Budget:
  • CPU / Mem / Disk usage monitoring:
  • Alerting Rules & Thresholds:

๐Ÿงช Summary Table

Area Metric Estimation/Notes
UsersDAU, MAU
TrafficRPS, Peak RPS, Payload Size
StoragePer User, Retention, Replicas
Read/WriteQPS, Ratio
ComputeCPU/Req, Instance Count
LatencyP95, P99, Timeout
CacheHit Ratio, TTL
AvailabilityRF, Downtime Tolerance
MonitoringErrors, Alerts, Saturation