CONFIGURATION
Login to your smallinvoice account via https://app.smallinvoice.com:
- Click Home
- Click Configuration
- Click Integration
- Click on the payrexx logo to configure the settings:
- Click Edit
- Enter your Payrexx Account name such as https://yourname.payrexx.com
- Insert the API Secret that you copied from the Payrexx backend (see next screenshot)
- Click the link and choose the PSP's and payment methods
- Enter the ID's of the PSP's and payment methods that you want to appear (you'll find the PSP ID's here: https://developers.payrexx.com/docs/miscellaneous
- Click Settings
- Click API
- Enter the URL https://app.smallinvoice.com/payrexx.php
- Choose Normal (PHP-Post)
- Click Save and wait
- Double click on the API Secret in order it gets blue and click the right mouse button
- Click "Kopieren" respectively "Copy"
USAGE
Create a new invoice:

- Click on PAYMENT
- Make sure that PAYREXX is set to "Generate and print"
Now the payrexx payment link appears on the invoice: