When the pro taps I've Arrived in their app, we generate a random 4-digit PIN and send it to you via push + email.
The pro sees the same PIN on their phone. Ask them to show it before you let them in, and confirm the number matches what we sent you. If it doesn't match, don't let them in — contact support immediately.
The PIN is single-use and expires after 15 minutes. If the pro is delayed and the PIN expires, they can tap Re-arrive to generate a fresh one.