App
Git
You accidentally committed sensitive credentials and pushed them to a shared branch.
How do you remove them from the entire history?
Redis
If Redis stores data in memory, what happens when the memory limit is reached?
You cache product prices in Redis with no TTL. Prices in cache are stale (different from database).
What’s wrong with your caching strategy?
SQL
Why does this query fail?
SELECT SUM(amount) AS total
FROM orders
WHERE total > 100
Web
What is SSL Handshake ?( which BTW is a very common interview question)
How are you going to start ?
A user clicks “Pay” twice by accident within milliseconds of each other.
Both requests hit your server at the same time.
How do you prevent them from being charged twice?
How does Amazon sync your cart across phone, laptop, web, and multiple devices in real time?
