Messaging
All interview questions related to Messaging
How do you scale a message queue system like Kafka or RabbitMQ to handle millions of messages per second?
You need reliable event publication coupled with database writes. Describe how you’d implement the outbox pattern and ensure idempotency end to end.
Design a web/mobile chat system with 1:1 and group chats, typing indicators, presence, read receipts, and offline support.
Design a service to send notifications via email, SMS, and push at scale with retries, templates, and user preferences.
Design a pipeline to ingest, process, and query billions of events per day with second-level latency and exactly-once semantics.
Design a reliable, horizontally scalable scheduler (distributed cron) that supports one-off and recurring jobs with retries and idempotency.
Design an email system that supports bulk sending, deliverability, spam compliance, tracking, and feedback loops.
Design a global publish/subscribe system with millions of subscribers, durable delivery, and filtering.
Design a ticketing and support system with multi-channel intake, prioritization, and SLA tracking.
Your Kafka consumer groups are showing high lag and messages are processing slowly. How do you investigate and remediate this?
Your RabbitMQ/SQS queue has millions of unprocessed messages. What steps do you take?