There are four main cloud-based platforms in the world. Amazon Web Services (AWS), Microsoft Azure, Google & AliBaba. We have chosen to use Microsoft Azure as our code and database are heavily reliant on Microsoft's platform. Microsoft has been one of the pioneers of computing over the last 35 years and they go from strength to strength with their new hosted model.
What we look for in a cloud provider is reliability and security. We operate Zahara safe in the knowledge that the platform it sits on is protected. It's a great base layer. It's then down to us to make sure our own boundary is secure and having Cyber Essentials Plus certification helps us operate to a high standard. We then try to proected our clients' data as best we can with two factor autnentication (planned release December 2019) being an example of a new standard of protection that everyone is now offering or planning to offer.
Every year we have to re-apply for our integration with Intuit's QuickBooks Online. Intuit run robest tests, similar to a penetration test - and check for any vulnerabilities in our code or any ways of accessing their customers data. We have passed every year.