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USection 01Notification Service
Problem Understanding
Restate the problem in your own words.
What this step looks like in a real interview: Read the problem statement and real-world examples, then write what the system is, who uses it, and the scope you'd commit to in a 45-minute round.
ProblemWhat you're designing
Notification Service
Asked atAmazon· SDE2Razorpay· SeniorSlack· Senior
Design a notification service: send a notification to a user across one or more channels (Email, SMS, Push). Each channel may have multiple providers (Twilio, SES). Templates render messages from a payload. Failover when a provider fails. Async send with retries.
Real-world examples
- Slack notificationsCross-device push.
- AWS SNSMulti-protocol fan-out.
- OneSignalMobile push notification SaaS.
Your task: read the problem above, then write what the system is, who uses it, the rough scope, and the headline non-functional concerns — in your own words. Submit for AI review when you're ready.
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Your understanding
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Senior-engineer feedback on what's strong, what's missing, and a calibrated score for this section.
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