There are several possibilities with URL schemes in Next.
You need to provide the category number and the amount, the note is optional. For example:
The sort order of your categories, beginning from 0 going to 26 for the last entry.
You can use x-callback-url to provide an url which gets called when Next added the expense (x-success parameter). This example would insert an expense and after that open safari (because we gave „http://„ as x-success parameter and the system associates this url with Safari):
You could for example create a button in Launch Center Pro which creates an expense for your „Coffee“ category (just set the number where your coffee category is, in our example it’s on position 3) for an amount of 3.99, adds a note with „Starbucks“ and then returns again to Launch Center Pro (which has an URL of „launch://„):