If you have multiple Stripe accounts for different apps it gets quite annoying to calculate tax owed per country in your quarterly 🇪🇺 EU OSS VAT and 🇬🇧 UK VAT filings.
For each of your Stripe accounts, go to your Stripe Tax > Registrations page, tap on the Export transactions button, select the date range you need (usually Last Quarter), select Summarized export and finally tap on Export to get the CSV file.
Then select all of those CSV files in this tool and hit Calculate. It will summarise the VAT owed in each jurisdiction.