Verify once. Reuse the proof.
A proof is a verifiable record of what was checked, who it belongs to, and whether it still holds. The next app checks the proof instead of repeating the check.
Portable proof means a verification result another system can check without repeating the original check.
Check a proof on your server
gate.ts

Check once. Reuse everywhere.
Run the check, keep the proof, and let the next system verify it instead of asking again.