cognito:username — Cognito Username

Location: payload · Vendor: AWS Cognito

The user pool's internal username for the account. For federated (social/SAML) sign-ins this is often a provider-prefixed synthetic value rather than anything the end user typed, and it can differ from sub even though both are meant to be stable per-user identifiers.

Defined in Amazon Cognito user pool tokens.

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