You
ParkPercent keeps your check-ins under an anonymous ID stored in a single cookie on this device. No account, no password.
Use on another device
Generate a short-lived code, then open the link (or scan the QR) on your other device. Codes work once, expire in 15 minutes, and ask for one confirming tap on the other device.
Your data
Heads up: without a recovery email (coming later), clearing your browser cookies orphans your data. Export a copy first if you care about it.