preferred_username — Preferred Username

Location: payload · Vendor: Microsoft Entra

A human-readable, display-oriented username (technically a standard OIDC claim, but the one Entra ID emits in place of upn on v2.0 tokens). It is explicitly not guaranteed unique or immutable — never use it as a lookup key, only for display.

Defined in Microsoft identity platform token reference.

Decode a JWT and inspect its preferred_username claim in the TokenPrism debugger — free, entirely in your browser.