IRLid lets two people prove they physically met — no app, no accounts, no biometrics required. Two phones. Two QR scans. One cryptographically signed receipt proving co-location within 12 metres at a specific time. ECDSA P-256 via the Web Crypto API. Entirely browser-based. v4: optional bio-metric confirmation (Face ID/fingerprint committed into the signed payload), privacy mode (GPS replaced with SHA-256 hash), trust history scoring. Open source. Free. One developer, UK, spare time.