What username/password/signature should I be using for the PayPal Sandbox?

问题

I'm trying to refund transactions using the Paypal NVP API. I've got some payments in a sandbox account, but when I try to issue a refund though the API I get You do not have permissions to make this API call. But I'm not sure what credentials I should be using.

According to the documentation, it says:

To access the PayPal API, you need API credentials, either an API signature or API certificate, that identify you. Use the following sample API signature and password in your sample programs that run in the PayPal Sandbox test environment.

API username sdk-three_api1.sdk.com
API password QFZCWN5HZM8VBG7Q
API signature A‑IzJhZZjhg29XQ2qnhapuwxIDzyAZQ92FRP5dqBzVesOkzbdUONzmOU

I tried generating API credentials for the sandbox merchant account that's issuing the refunds, but the Paypal website crashes every time I try. Are these the correct credentials? What do I need to do to test this?

回答1:

Your test accounts do not have credentials.

To get started with Payment Card in Sandbox, you must first create a buyer test account and enable in-store checkout.

After login sandbox you will find that option in menu API and Payment Card Credentials and then click it you will get option Create Test Account and after create account you will get API Username, API Password and Signature.

Use those API Username, API Password and Signature in your application.

回答2:

I found these details in my account after logging in:

go to the sandbox tab

below this you will find Accounts. Click on Accounts.

All your email lists will be shown.

Click on the email id that belongs to the Business account.

You will see two options: profile and notifications below the email id's.

After clicking on profile one window will pop up with name Account details.

In that you will see the tab API Credentials. In this you will find your username, password and signature. Please note : You will find these details only in your Business type account, not for buyer type.

来源：https://stackoverflow.com/questions/10033940/what-username-password-signature-should-i-be-using-for-the-paypal-sandbox