In PayPal Developer Dashboard, go to Apps & Credentials Switch to Sandbox tab Under "REST API apps", click "Create App" (or use existing default app) You'll see:
                
                    Client ID - Used to identify your application
                    Secret - Keep this secret and secure Client ID - Used to identify your application Secret - Keep this secret and secure Copy both Client ID and Secret for sandbox testing Create a Production app using the same process for live payments Credential Type Example Usage Visibility Client ID ASO...long string...xyz Frontend - Identifies your application to PayPal Can be public Secret ELX...long string...abc Backend - Authenticates your app to PayPal API Must be private