Core functional requirements: create a short URL, redirect a code to its destination, optionally set expiration, and allow authenticated owners to inspect or disable links. Non-functional goals may include low redirect latency, high read availability, abuse resistance, and durable mappings.

Define POST /v1/links, GET /{code}, and owner-management endpoints. Use an opaque code and store destination, owner, creation time, expiry, and status. Estimate create and redirect rates separately; redirects are usually much more frequent than link creation.

Choose a code-generation strategy that avoids collisions at the expected scale. Random codes need collision detection and retry; a counter-based generator needs coordination and may expose creation order. The code length should be based on the alphabet size and collision expectations, not guessed casually.