← Lab

Build a URL shortener

Users paste a long URL and get a short link. About 40 new links/second, about 4,000 redirects/second (100 reads per write). Redirects must feel instant.

Architecture so far

redirectCLIENTBrowserSERVICEURL servicestateless replicas

Decision 1 of 6

Every link needs a short, unique code. You will create about 100 million links per month across many servers.

How do you produce the codes?