Scaling Reads and Fighting Abuse

Your shortener has grown to 200,000 redirects/s at peak, and the trust and safety team reports two problems: phishing links using your trusted domain, and a bot that seems to be walking through your key space.

1. Describe how you would scale the read path to 200,000 redirects/s while keeping p99 latency under 50 ms globally.
2. How do you make it uneconomical for a bot to enumerate keys?
3. Design the flow for taking down a phishing link so it stops resolving everywhere within seconds.