Manual Key Exchange

There are two options for the manual key exchange. Both involve the merchant copying a JSON object and pasting it into a field in the Ecommerce provider’s plugin configuration screen. In one option, the payload will be encrypted; in the second option, it will be in plain text. The Ecommerce provider plugin should provide a field (preferably a textarea element) where the merchant can paste either of these two payloads.

Encrypted copy/paste : For the encrypted copy/paste method, the merchant will copy the encrypted credential payload displayed during the registration workflow. When the payload has been submitted, you can determine that it is encrypted by testing if the encryptedPayload key exists in the JSON object. If present, follow the instructions in the How to decrypt credentials section to decrypt the underlying merchant credentials.
Plain text copy/paste : For the plain text copy/paste method, the merchant copies the plain text credential payload (JSON format) from Seller Central. When the payload has been submitted, you can determine that it is plain text by testing if the merchant_id key exists in the JSON object. If present, follow the instructions in the How to process plain text credentials section to retrieve the credentials from the JSON object.

Troubleshooting

When the Amazon Pay Account Conflict error appears on the Share Credentials page:

Go to your eCommerce solution provider's configuration panel.
If the Reset Configuration option is available, use it to clear the existing setup.
Re-enter your Amazon Pay account details.
If the Reset Configuration option is not provided, or the issue continues after resetting, proceed with the manual key exchange process mentioned below

Manual Key Exchange Process

Navigate to Amazon Pay Integration Central: US, EU, JP.
Under section Guides, keys and IDs to connect your store, in the drop-down menu, choose your eCommerce solution provider, and then choose your version then, Click Get instructions.
Create a public/private key pair a. Navigate to the API keys section b. Click on the Create keys button c. Use the default Generate API credentials setting d. Name your API keys. Use a descriptive name, the name will be used to differentiate between multiple keys when you need to manage them in Integration Central. When naming the keys, you should consider who is using it and what they’re using it for e. Click Create keys to create the public/private key pair.
Store the private key and Public Key ID a. Creating the key pair will automatically download the private key (.pem) file to your browser, you do not need the public key. Save the private key file in a secure location, you will need it to access Amazon Pay APIs. You should never share your private key with anyone and this is the only time that you will be able to download the private key file. If you lose access to your private key, you must generate a new key pair. b. Store your Public Key ID, you will need it to access Amazon Pay APIs. Unlike the private key file, you can return to this page at a later time to access your Public Key ID
Take the keys obtained from Seller central & fill in eCommerce solution provider's configuration panel