Use TLS for all connections, prefer modern cipher suites, and enforce HSTS. Encrypt sensitive fields at rest with managed keys, rotate secrets, and restrict access by role. Tokenize or redact personally identifiable information where possible, limiting blast radius if a credential leaks or a laptop goes missing.
Assume timeouts and partial failures. Implement retries with exponential backoff, idempotency keys, and dead-letter queues. Emit structured logs and traces to observe behavior across services. With graceful degradation and alerting thresholds, a transient vendor issue becomes a contained event, not a multi-team scramble at closing time.
Map where personal or financial data flows, classify sensitivity, and set retention aligned to business and legal needs. Prepare subject access processes, breach notifications, and vendor assessments. Clear accountability and documentation turn regulatory requirements into normal routines that protect customers and preserve agility during growth and change.