Fault tolerance in cloud architecture refers to the ability of a system to keep running even when some components fail. Cloud platforms achieve this by using techniques such as redundancy, automatic failover, load balancing, and data replication across multiple availability zones or regions. Major cloud providers like Amazon Web Services, Microsoft Azure, and Google Cloud offer built-in services that help organizations design highly available and resilient applications. When building fault-tolerant systems, companies should focus on important factors such as system resilience, continuous monitoring, proper load balancing, and strong disaster recovery planning so applications remain stable, reliable, and accessible even during unexpected failures.