Vendor lock-in (AI)

Vendor lock-in in AI is dependence on one provider's models and interfaces to the point that switching requires rebuilding the systems above them. It matters more than in most software categories because model capability and pricing move quickly, so a fixed choice ages faster than the applications built on it.

Lock-in is rarely a single decision. It accumulates through provider-specific features, prompt formats tuned to one model's behavior, and evaluation suites that only measure the incumbent.

The structural defense is an orchestration layer that keeps the choice of model separate from the application logic, so switching is a routing change rather than a migration.