Set up PayPal on your website with these Instructions
Click on the "Revenue Tab" > "Integrations" > "Connect"
Copy and paste the IDs into the appropriate fields and click "Save"
Get started with PayPal REST APIs
PayPal APIs use REST, authenticate with OAuth 2.0 access tokens, and return HTTP response codes and responses encoded in JSON. You can test US integrations with a PayPal Developer account.
Get Account ID and Account Secret ID
PayPal integrations use a Account ID and Account secret to authenticate API calls:
A account ID identifies an app. You only need a Account ID to get a PayPal payment button and standard credit and debit card fields.
A account secret authenticates a account ID. To call PayPal APIs, you'll exchange your account ID and account secret for an access token. Keep this secret safe.
Here's how to get your account ID and account secret:
Select Log in to Dashboard and log in or sign up.
Select Apps & Credentials.
New accounts come with a Default Application in the REST API apps section. To create a new project, select Create App.
Copy the account ID and account secret for your app.
Get Sandbox Account Credentials
The PayPal sandbox is a test environment that mirrors real-world transactions. By default, PayPal developer accounts have 2 sandbox accounts: a personal account for buying and a business account for selling. You'll get the login information for both accounts. Watch sandbox money move between accounts to test API calls.
Take the following steps to get sandbox login information for business and personal accounts:
Log into the Developer Dashboard.
Select Testing Tools > Sandbox Accounts. You can create more sandbox accounts by selecting Create account.
Locate the account you want to get credentials for and select.
Select View/Edit Account to see mock information such as the account email and system-generated password.
Go to sandbox.paypal.com/signin and sign in with the personal sandbox credentials. In a separate browser, sign in with the business sandbox credentials.
Make API calls with your app's access token to see sandbox money move between personal and business accounts.