Spotify Client ID

From developer.spotify.com/dashboard → your app → Client ID

Redirect URI

Must be registered in your Spotify app's "Redirect URIs". To serve this file:
python3 -m http.server 8000 then open http://localhost:8000/setlist-to-spotify.html

setlist.fm API Key

From setlist.fm/settings/api

CORS Proxy URL (for setlist.fm — leave default unless broken)

The setlist.fm API doesn't support browser CORS, so requests are routed through a proxy. Default: https://corsproxy.io/?