URL Shortener

Build a production-ready URL shortener with user accounts, custom aliases, redirect handling, click analytics, expiration policies, and API access. Model short links, redirect targets, click events, rate limits, and API credentials explicitly. Include abuse prevention for malicious links, resilient redirect behavior under heavy read traffic, observability for redirect latency and analytics lag, audit logs for destructive link changes, and a design that separates hot redirect paths from slower analytics aggregation so link resolution stays reliable.