Breaking platform lock-in: the de-risking checklist

Heard this week: a managed WP shop adding 'proprietary' caching that doesn't port. The crowd that stays mobile audits lock-in on a schedule:
— Catalog every host-specific plugin or mu-plugin you can't run elsewhere.
— Confirm your CDN and edge rules are reproducible off-platform.
— Test a full export-import on a throwaway host quarterly.
— Document any custom redirect or rewrite logic living in their dashboard, not your repo.
— Keep DNS and email separate from the hosting account entirely.
A source tells us the proprietary features are sold as performance and built as handcuffs.
Watch this: 'platform-exclusive' optimization is the new exit tax.