Configuration - Smallinvoice

Log in to your smallinvoice account via
  1. 1.
    Click "Home"
  2. 2.
    Click "Configuration"
  3. 3.
    Click "Integration"
  4. 4.
    Click on the Payrexx logo to configure the settings:
  1. 1.
    Click "Edit"
  2. 2.
    Enter your Payrexx account name such as
  3. 3.
    Insert the "API Secret" that you copied from the Payrexx backend (see next screenshot)
  4. 4.
    Click the link and choose the PSP's and payment methods
  5. 5.
    Enter the IDs of the PSPs and payment methods that you want to appear (you will find the PSP IDs here:

Configuration - Payrexx

  1. 1.
    Click "Settings"
  2. 2.
    Click "API"
  3. 4.
    Choose "Normal (PHP-Post)"
  4. 5.
    Click "Save" and wait
  5. 6.
    Double click on "API Secret" so it gets blue
  6. 7.
    Copy the text by clicking the right mouse button and then clicking on "Copy" or by using CTRL+C


Create a new invoice:
  1. 1.
    Click on "PAYMENT"
  2. 2.
    Make sure that PAYREXX is set to "Generate and print"
Now the Payrexx payment link appears on the invoice: