Step 4 - Wrap up

We talked about the API design, data model, hash function, URL shortening, and URL redirecting.

If there is extra time at the end of the interview, here are a few additional talking points.

• Rate limiter: A potential security problem we could face is that malicious users send an overwhelmingly large number of URL shortening requests. Rate limiter helps to filter out requests based on IP address or other filtering rules. If you want to refresh your memory about rate limiting, refer to “Chapter 4: Design a rate limiter”.

• Web server scaling: Since the web tier is stateless, it is easy to scale the web tier by adding or removing web servers.

• Database scaling: Database replication and sharding are common techniques.

• Analytics: Data is increasingly important for business success. Integrating an analytics solution to the URL shortener could help to answer important questions like how many people click on a link? When do they click the link? etc.

• Availability, consistency, and reliability. These concepts are at the core of any large system’s success. We discussed them in detail in Chapter 1, please refresh your memory on these topics.