Implicit Grant Flow (OAuth)
The Implicit Grant Flow is a streamlined authorization method within the OAuth 2.0 protocol, primarily used in client-side applications such as single-page applications (SPAs) or mobile apps. Unlike other flows, it directly returns an access token to the client without requiring an intermediate server-side exchange.

This flow operates as follows:

The client redirects the user to the authorization server's login page.
After successful authentication, the server redirects the user back to the client, including the access token in the URL fragment.
The client extracts the access token and uses it to access protected resources on behalf of the user.
The Implicit Grant Flow was designed for environments where client secrets cannot be securely stored, such as in-browser JavaScript or mobile apps. Its simplicity makes it lightweight and fast, but it has security limitations. Because the access token is exposed in the URL and stored in the client, it is more vulnerable to interception or misuse.

To mitigate these risks, it is recommended to use secure HTTPS connections, enforce short-lived tokens, and leverage modern alternatives like the Authorization Code Flow with PKCE (Proof Key for Code Exchange), which addresses many of the implicit flow's vulnerabilities.

While the Implicit Grant Flow is still supported, evolving security standards and the shift toward more secure options have led to its declining adoption in favor of safer, more robust OAuth flows.