Langouste is free to use. Pro adds more for people who type in several layouts.
Not for the free app: it works offline and sends nothing anywhere. You sign in only to use Pro, so the licence can follow you across up to five devices.
Pro stays until the end of the period you paid for, then the app returns to the free features. Your groups and shortcuts keep working.
Yes. Paddle, our reseller, sends a tax invoice with every payment; add your VAT number at checkout.