I jumped straight into token formats and OAuth flows before even asking what was wrong with the current system.
Start by clarifying the current system's constraints, the new system's goals, and the migration's success criteria. Then outline a phased, risk-mitigated plan that prioritizes backward compatibility, incremental rollout, and rollback strategies. Emphasize security, user experience, and data integrity throughout.
Pro tip: Highlight the importance of a dual-write/dual-read period and feature flags to enable gradual migration and instant rollback. Also, discuss how you'd handle edge cases like password resets and token invalidation during the transition.
Understand the current authentication system's architecture, user base, and dependencies. Define clear goals for the new system (e.g., improved security, scalability) and success metrics.
Choose a migration pattern (e.g., big bang, phased, parallel run) based on risk tolerance. Plan for data migration, user credential transfer, and session management.
Roll out the new system to a small subset of users first, using feature flags and canary releases. Ensure backward compatibility and provide fallback mechanisms.
Continuously monitor authentication success rates, latency, and error logs. Validate that the new system meets requirements and iterate based on feedback.
After full migration and a stability period, decommission the old system, ensuring all data is migrated and no dependencies remain.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.