This is what it says on the tin. It's a website that lists startups from London.
Here's the website: startupsinlondon.xyz
You can use the search function, or the dropdown to filter companies based on their business category (fintech, health etc).
I've been wanting to play around with Next.js for a while, as it's meant to be quite powerful, allowing you to render pages statically, making the API calls at build-time, or making API calls per request very trivially.
The source code for this website can be found here under an MIT license