ApexArchitect (Hardest)managed-packagesisvextensibility
Design package-friendly Apex for ISV and managed package contexts
Real World Scenario
ISV product needs extension points for customer-specific logic without modifying base package Apex.
Expected Answer
• Global virtual classes and interfaces for customer override implementations
• Protected vs public Apex API surface documented in release notes
• Extension hooks via Factory pattern reading Custom Metadata implementors
• Avoid global variables; use subscriber-controlled CMDT for configuration
• Namespaced test utilities for customer test isolation
• Semantic versioning for global method signature changes
• Post-install script setting up default CMDT records
Follow-Up Questions & Answers
Click to expand — each follow-up includes a direct, interview-ready answer
Main difference: use case and scale. Global virtual classes and interfaces for customer override implementations. Protected vs public Apex API surface documented in release notes. Pick based on your integration pattern and team capability. ISV Apex is API for customers—breaking global methods without migration path destroys trust. Document the decision in an ADR and align with enterprise standards.
Architect Perspective
ISV Apex is API for customers—breaking global methods without migration path destroys trust.