2 answers published. Last candidate submission on Aug 26 2026, 4:10pm PDT. Interview question asked to Machine Learning Engineers, Software Engineers, Engineering Managers and other roles interviewing at Staples, Pendo, Cloudflare and other companies. Original question asked: Design a messaging system like WhatsApp.. Question last reported by a candidate interviewing at Wayfair for an Engineering Manager interview on Aug 22 2026, 8:42am PDT.