Instagram improved performance by storing frequently accessed images closer to users. Which technique was applied?

A digital bank upgraded its CPUs and RAM to handle transaction volume. This is an example of:

Which situation benefits MOST from horizontal scaling rather than vertical scaling?

Airbnb avoided crashes during peak travel by:

If a company wants to reduce downtime when one load balancer fails, the BEST solution is:

Which load balancing method ensures one user session always connects to the same server?

A news website wants its pages to load faster worldwide. Which strategy should they implement?

Which caching policy risks removing popular but 'old' items first?

A system requires the fastest possible responses with lowest latency. Which load balancing algorithm fits best?

An e-commerce company improved search by indexing database queries. This is an example of:

A social media app used Redis for caching profile data. Why was this effective?

If a load balancer goes down and DNS automatically redirects traffic to a backup, this is known as:

Why is horizontal scaling often more fault-tolerant than vertical scaling?

Which case BEST represents performance optimization?

An e-commerce site integrates PayPal payments using its API. What principle does this show?

A developer reuses Google Maps API in multiple apps. Which benefit of APIs is highlighted?

A company updates its internal algorithm but keeps API endpoints the same. Which API principle is maintained?

Twilio makes money offering APIs for SMS and calls. This demonstrates:

Which HTTP method in REST is used to update an existing resource?

API versioning is MOST needed when:

A banking API requires OAuth tokens before returning data. This shows:

If an API endpoint is modified but still works with old client apps, what practice ensures backward compatibility?

Postman is MOST useful for:

A team wants API documentation that allows interactive editing and hosted docs. Which tool suits this need?

Uber monitors microservices proactively to avoid ride disruptions. Which practice is demonstrated?

Which tool is open-source and widely used for monitoring with metrics and visualizations?

Nagios is best suited for monitoring:

A system fails but automatically switches to backup resources. This is called:

An e-commerce site lets users continue browsing even if payment gateway is down, but checkout is disabled. This is:

Which error type is caused by user actions, like invalid form input?

A company sets up alerts and logs for recurring issues. This practice is:

Why is structured logging better than plain text logs?

Which debugging practice helps inspect variable values step by step?

Why is centralizing logs important in complex systems?

A bank consolidates transactions every night. What integration type is this?

If a system updates a hotel booking instantly across databases, which integration type applies?

Which integration method avoids duplication by creating a logical view instead of moving data?

In batch ETL, why is parallel processing beneficial?

Which case BEST fits real-time data integration?

A telecom firm moves CRM data from legacy to cloud CRM in one-time process. Which pattern applies?

During migration, what prevents data loss?

A stock trading company streams live stock data to clients continuously. This is an example of:

Bi-directional synchronization ensures:

A retail chain synchronizes customer profiles online and offline. Which issue is MOST common?

An e-commerce site correlates sales and feedback data to improve recommendations. This is:

Why is aggregation used in smart city IoT projects?

Edge computing supports aggregation by:

Which integration pattern ensures data is updated across both systems but not irrelevant fields?

A financial firm moves large volumes of stock data, compresses it, and replicates across clients. Which challenge are they solving?