StaffSignal

Design WhatsApp

Design WhatsApp — A Staff+ playbook focused on message delivery guarantees, E2E encryption key management, group messaging fan-out, and presence at scale — not just WebSocket chat demos.

This playbook is part of the full calibration library.

Staff interviews are decided on nuance — tradeoff framing, ownership boundaries, and failure anticipation. This topic includes evaluator-grade breakdowns and drill sections available with full calibration access.

What's inside this playbook

  • Staff-level tradeoff analysis and failure mode reasoning
  • L5 vs L6 calibration tables for this specific topic
  • Practice drills with Staff-level evaluation criteria
  • Deep-dive appendices and operational ownership patterns