Real-Time on Rik Kisnah - Bloghttps://www.rik-kisnah.ai/tags/real-time/Recent content in Real-Time on Rik Kisnah - BlogHugoenTue, 21 Apr 2026 09:00:00 -0700Design a One-to-One Chathttps://www.rik-kisnah.ai/teach/systems/design-a-one-to-one-chat/Tue, 21 Apr 2026 09:00:00 -0700https://www.rik-kisnah.ai/teach/systems/design-a-one-to-one-chat/One-to-one, text only, web only. That is all the interviewer gives you. Ask for the rest, then design the gateway that finds the recipient, the inbox that survives them being offline, the presence key that expires on its own, and defend Redis Pub/Sub against Kafka out loud.