Polr
A modern, powerful, and robust URL shortener
...Modern and simple interface to manage your links and control your instance. Run-on your own domain to adjust your branding to perfection. Use Polr out of the box or fork the code to tweak it to to your needs. Customize your instance's shortening permissions, redirects, or even its theme. Semantic REST API for integration with other services. Assign new API keys to users automatically, or generate them manually. Create new links or look up existing links without modifying your breaking your existing code. For more information, see API docs.