Xero is perfectly safe to use all day, every day. If it wasn’t we wouldn’t be using it.
Here’s just a taste of the security protection that Xero offers:
Certified as compliant with ISO/IEC 27001:2013, the global  information security management system (ISMS) standard.
Complies with Payment Card Industry Data Security Standard (PCI DSS v3.2, SAQ A.
Xero uses industry-standard TLS (Transport Layer Security) to encrypt all your data.
Applies a defence-in-depth approach using multiple security controls, including firewalls, intrusion protection systems, and network segregation.
Features multiple secure data centres within enterprise-grade hosting facilities, in geographically-separated locations.
Employs a security team to continuously monitor its security systems, event logs, and notifications, to identify and manage any threats as they appear.