We are working on New Zealand, but don't have an immediate ETA for an New Zealand beta. Sign up at https://stripe.com/global to be notified when we launch
South Africa is on our roadmap, but have no current ETA for when it will be available. Please sign up at https://stripe.com/global to be notified when we launch.
Stripe AU supports AMEX (as well as Visa and MasterCard!), but is currently only for AUD charges. We are actively working on adding USD support, and hope to roll it out soon. Email me @ [email protected] if you would like a beta invite.
You can accept payments with credit and debit cards from customers anywhere in the world. Currently the Stripe UK and Ireland betas support Visa and MasterCard, with American Express payments coming soon
Stripe allows US and Canadian businesses, and is in closed beta in the UK (sign up at https://stripe.com/global if you would like an invite!) We definitely want to launch in many more countries, but can't say much about timelines as yet.