Mercor | System Design Assessment | Complete Solutions & Tips | Real-Time Chat Application | Campus Assessment

System Design Exercise Design a real-time chat service supporting one-on-one and group conversations. Endpoints POST /conversations — create a new conversation given a list of participant user IDs. POST /conversations/[conversation_id]/messages — send a message to the specified conversation. GET /conversations/[conversation_id]/messages — fetch message history; support pagination and time-range filters. GET /conversations — list all conversations for the authenticated user with metadata (e.g., unread count). Key Requirements Real-time delivery: ensure low-latency message delivery over a persistent bidirectional protocol (e.g., WebSockets or ...