System Design Interview Skill

Structures a complete, interview-grade system design response — covering clarifying questions, requirements, capacity estimates, architecture, component design, and trade-offs. Works equally well for real architecture sessions.

Required Inputs

Ask for these if not provided:

• The system to design (e.g. "design a URL shortener", "design a notification service", "design Twitter's feed")
• Scope (interview prep / real architecture decision / practice run)
• Scale target (rough numbers: DAU, requests/sec, data volume — or "assume typical web scale")
• Constraints or priorities (e.g. prioritise availability over consistency, minimise cost, low-latency reads)
• Time available (interview context only: 30 / 45 / 60 minutes — skip for real architecture sessions)
• Emphasis (optional — any area to go deeper on, e.g. "focus on the DB design" or "spend more time on scaling")

Output Format