Same as any other entity (or person).

Entity pays taxes in it's domicile jurisdiction.

Best you talk with a tax preparer in your home country to ensure you have all the details.

And... If you're a US citizen + your SAAS company is generating massive cash, likely best to organize your entity in a low tax jurisdiction, like Bermuda which is home to Google, Intel, Verizon, etc.

And... best wait till Trump's new tax bill passes. If he has his way, corporate taxes may drop to a point low enough to keep your business in the US.