OAuth 2.0 Implicit Grant

tools.ietf.org/html/rfc6749#section-1.3.2

The Implicit grant type is a simplified flow that can be used by public clients, where the access token is returned immediately without an extra authorization code exchange step.

It is generally not recommended to use the implicit flow (and some servers prohibit this flow entirely). In the time since the spec was originally written, the industry best practice has changed to recommend that public clients should use the authorization code flow with the PKCE extension instead.

The OAuth 2.0 Security Best Current Practice document recommends against using the Implicit flow entirely, and OAuth 2.0 for Browser-Based Apps describes the technique of using the authorization code flow with PKCE.

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