Penultimate Guitar is an alternate frontend for Ultimate Guitar that makes it much more usable on mobile, rather than forcing the user to install the app.
It is built with TypeScript, Next.js, and Tailwind and deployed on Vercel. It works in tandem with a Postgres instance on a DigitalOcean through Prisma. The source code takes a lot of inspiration from Alculator.
The source code is available here. The deployed version can be found here.