[simple10]

Not to dis Polr, but if performance and minimalism are your thing, there are a lot of nginx + lua + redis URL shorteners on github.

Two random'ish selections...

https://gist.github.com/MendelGusmao/2356310

https://github.com/sanshi0518/shorturl-nginx

[lsaferite]

Just a few seconds of searching for a go based one yielded: https://github.com/samwierema/go-url-shortener

[dozzie]

Minimalism and Redis don't go hand-in-hand at all.