Simple OAuth2 Client is a free chrome extension that simplifies the process of obtaining an access token via the authorization code flow for development purposes. With this extension, users can easily retrieve an access token without the need to set up a separate application or server to handle OAuth2 redirection.

To use the extension, simply open the developer tools in Chrome and navigate to the Simple OAuth2 Client tab. From there, fill in the necessary configuration sections, including the redirect URI. This URI can be copied from the Client Config section and pasted into the "Redirect URIs" setting of your OAuth2 app.

Once the configuration is complete, click the "Start Auth" button. The extension will then open the authorization URL with the required parameters. Users will be prompted to sign in to the platform and grant access to the specified scopes.

Behind the scenes, Chrome securely handles the redirection by using the launchWebAuthFlow API. The extension retrieves the authorization code and exchanges it for an access token, which is then displayed to the user.

Simple OAuth2 Client supports several features, including the ability to specify any URL for the authorization and token endpoints. It also supports both public and confidential clients, as well as PKCE (S256 and plain) and non-PKCE requests. Users can choose between using the Authorization Header or Body Parameter for token request authorization.

With its user-friendly interface and straightforward functionality, Simple OAuth2 Client is a valuable tool for developers in need of quick and easy access token retrieval.