Guide for full stack developers to secure cloud apps: apply IAM/least privilege and MFA, encrypt data in transit and at rest, segment networks (VPCs, subnets, firewalls), enable logging/monitoring, and patch regularly. Map efforts to NIST CSF, ISO 27001, PCI-DSS, and HIPAA/HITECH via risk assessment, security policy, controls, and continuous audits—illustrated with fintech/healthcare use cases.