If you want to use PayPal Express Checkout to accept payments on Storefront, first of all you need to have a merchant account with them. If you don't have one already, please go here to apply.
Once you have a merchant account, you will need to log into your PayPal account and follow these steps:
1. Hover over 'Profile' and select 'My selling preferences' from the drop-down menu.
2. Click on the 'Update' button next to 'API access'.
3. Click on the 'Enable PayPal Express Checkout' link
4. Select 'Accept PayPal payments' and click 'Submit'.
5. On the next screen,you'll be shown a confirmation message acnowledging the changes you've made.
6. Now you'll need to go back to the 'API access' screen - see step 2.
7. Click 'Request API credentials'
8. Tick 'Request API signature' and click 'Agree and submit'.
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9. In the next screen, you will see a series of codes - copy these down safely, as you will be asked for them in the next step.
You're now almost ready to go! Log into your Storefront account and click 'Settings'. Select 'Payment methods' and click 'Add new'. Select 'PayPal Express' and click 'Save details'.
Click 'Edit' beside PayPal Express and go to 'Settings' on the left-hand side.
Now just fill in the details you generated in step 9.
Testing this payment system
If you want to test PayPal Express before you start selling live, you can do this by keeping the 'Use Sandbox' box ticked. Instead of filling in live 'Production' codes, you'll need to create a Sandbox account specially for testing - you can do this here.