What Is Vendor Lock-In?

A quick definition, the four types that actually matter, and where to go for the full cost breakdown.

Quick answer

Vendor lock-in is a situation where switching away from a vendor is harder or more expensive than staying, because of contractual terms, data formats you can't easily export, integrations built around the vendor, or infrastructure that only works on that vendor's servers. It's not inherently bad — most vendor relationships involve some degree of it — but it becomes a real risk when the cost of leaving grows without you deciding it should, and you don't find out how much until you actually try to leave.

The four types

• Contractual lock-in — a term commitment with an early-termination penalty, or an auto-renewal clause you'd have to actively cancel before a deadline.
• Data lock-in — your data lives in a format or system you can't easily export or reuse in a competing tool.
• Integration lock-in — other tools in your stack are built to depend on this one, so removing it breaks more than the single workflow it was bought for.
• Infrastructure lock-in — the product literally cannot function without this specific vendor's servers, with no offline mode or independent fallback. This is the layer that shows up most in AI tools specifically, where prompts, fine-tunes, and embeddings are often tied to one provider's environment.

Most conversations about lock-in only cover the first type — the contract. The other three are frequently the more expensive ones, and they're rarely documented anywhere you'd think to check before you're already dependent on the vendor.

Why it's worth pricing out, not just worrying about

Surveys consistently find that most organizations are concerned about vendor lock-in without having actually calculated what it would cost them — see our full vendor lock-in cost breakdown for the survey data and four real cases where the cost turned out to be catastrophic rather than hypothetical. If you're evaluating a specific AI vendor relationship, our piece on what actually breaks when switching AI vendors covers the layer of lock-in that doesn't show up in any contract at all.