Vendor lock-in
Vendor lock-in is a situation where leaving a supplier costs so much, in money, disruption, or lost assets, that staying stops being a choice. On websites it usually means the domain, hosting, CMS, or site itself lives in the vendor's accounts, so the switching cost does the retention work the service should be doing.
In practice
The term comes from enterprise software, but the website version is more personal: an established company discovers, usually at the moment it wants to leave, that its domain is registered to the agency, the site runs on the agency's hosting, and the content lives in a system only the agency can operate. None of that was hidden, exactly. It accumulated through convenience, one reasonable setup decision at a time.
Lock-in is not the same as commitment. A contract term you chose, with an exit you understood, is a deal. Lock-in is when the exit was never priced: proprietary platforms that cannot export, rental-model plans where cancelling deletes the site, or ownership arrangements where the practical answer to "can we leave?" is "not without starting over." The test is simple: could you change vendors in ninety days and keep your domain, your content, your rankings, and your data? If any answer is no, that is the lock-in, located.
The costs are mostly invisible until they are not. Locked-in companies pay above-market rates without noticing, wait longer for changes than the work requires, and accept service levels they would never accept from a vendor who had to re-earn the account, because the alternative is a migration priced to discourage it. The lock-in does not have to be enforced to work; it only has to exist.
The countermeasure is owning the pieces that cannot be rebuilt, whoever does the work: the domain registered to your company, hosting in your name, an administrator role in the CMS, analytics under your account, and a contract that says what transfers on exit. A vendor can hold delegated access to all of it and do excellent work; the difference between access and ownership is the difference between a contractor with keys and a contractor on the deed. A fifteen-minute check covers the essentials: do you actually own your website?
Open platforms and portable data lower the exit cost but do not remove the question. Even on open-source software, lock-in reappears through hosting arrangements, bespoke plugins, and technical debt that makes any change feel dangerous. Lock-in is a property of the arrangement, not the technology.
Common questions
What is vendor lock-in in plain terms?
It is when leaving a supplier would cost you so much that you effectively cannot, so you stay for the wrong reason. With websites it typically means the vendor holds your domain, hosting, or site, and the price of leaving is rebuilding some or all of it from scratch.
How do I know if I am locked in to my web vendor?
Ask what you could take with you in ninety days: domain, content, design, rankings, analytics history. If the honest answer is that leaving means losing assets or starting over, you are locked in to that degree. The registrant on your domain and the ownership clause in your contract are the two fastest places to check.