In both Marketpress and Fundraiser are options that require you to receive a special App ID. Marketpress requires this for Chained Payments, and Fundraiser requires this for Crowdsourcing.

The following is a basic outline of the general workflow that you would encounter when setting this up in either plugin. It will start with Getting the PayPal API and progress through the x.commerce application.

The first portion of the process requires you to activate and fill in your API Information.

An API signature consists of an API username along with an associated API password and signature, all of which are assigned by PayPal. You need to include this information whenever you execute a PayPal API operation.

To create an API signature:
1. Log in to PayPal, then click Profile under My Account.
2. Click My selling tools.
3. Click API Access.
4. Click Request API Credentials.
5. Check Request API signature and click Agree and Submit.

Then you'll see a screen similar to the following:

This information will fill all but one box. The final box is preceded by a note:

You must register this application with PayPal using your business account login to get an Application ID that will work with your API credentials. A bit of a hassle, but worth it! In the near future we will be looking for ways to simplify this process. Register then submit your application while logged in to the developer portal. Note that you do not need an Application ID for testing in sandbox mode. More Information »

Here is where the special Permission comes in. You have to submit your application, giving some basic details of your site, just so that PayPal knows you're not a scam site and legitimately processing delayed payments.

So, it's easier than you think. Just visit this link https://www.x.com/developers/paypal

Then click Sign Up in the upper right corner.

You will be asked to register with your ebay or PayPal account information. This is the only way you can register, there is no separate password/username for this site.

Once you are registered and logged in you will need to Navigate to “My Account” in the upper right corner. Then click “New App” in the left menu that comes up.

OK, now here is your cheat sheet for the application! There will also be two example applications at the end. One for Marketpress and one for Fundraiser.

Once that's done, it's a waiting game. It usually takes about a week, but may take up to 10 days if there are no issues.

You may get an email saying more information is needed. If so, just visit your account page and click on “Status Messages” and reply accordingly.

Once you have been approved you will receive a letter like this via email containing the APP ID:

Simply transfer the ID to the appropriate box in your plugin payments page and you are ready!

Here are a few tips direct from the x.commerce folks for filling out your app:

Also, here are a few pointers for the App Review process to make it as speedy as possible (this assumes the prerequisites such as a Premier or Business Verified account are already fulfilled):

- Only select API's in the 'Services Used by App' section of the x.com submission that your app is currently using.

- For all API's selected, we will need to test the payment flow against our Sandbox test environment. Please provide all details for this in the 'Testing Information' section:

URL’s, test accounts for your site, test items, etc.

- If you are using Preapprovals (i.e. an 'Advanced' API), please attach a Cert. of Incorporation or similar document showing your company as a currently registered business entity to the 'Business Information' section of your submission.

- If you have selected 'Chained Payments', please ensure to complete the Primary and Secondary Recipient fields aswell as the 'Who pays the fees' selection.

- For all API's, please ensure to include an estimate of your average transaction price and monthly payment volume in the 'Expected monthly payment volume and average transaction amount in US$' section.