It is perfectly possible to pay your subscription on a monthly basis.
I am a first time FibriCheck user
STEP 1: Download and open the FibriCheck app.
STEP 2: Create your individual account. (Click here for more information).
STEP 3: You are now taken to the start page. Tap 'Start measurement'.
STEP 4: Tap ‘Choose your subscription plan’. This is where you can either opt for an Essential or a Premium subscription plan before selecting whether you wish to pay your subscription once a year or in monthly installments.
I have previously used FibriCheck and I use an iPhone
STEP 1: Go to ‘Settings’ on your iPhone.
STEP 2: Tap ‘Apple ID, iCloud, ‘Media and purchases’.
STEP 3: Tap ‘Subscriptions’.
STEP 4: Tap ‘FibriCheck’ in the list of active subscriptions.
STEP 5: Select ‘FibriCheck Premium Monthly’ or ‘FibriCheck Essential Monthly’.
I have previously used FibriCheck and I use an Android smartphone
STEP 1: Open the FibriCheck app.
STEP 2: Tap ‘Settings’ at the bottom right of your screen.
STEP 3: Tap ‘My subscriptions’ in the menu.
STEP 4: Tap ‘Change subscription’.
STEP 5: Select ‘FibriCheck Essential Monthly’ or ‘FibriCheck Premium Monthly'.