The reason a platform’s rules change after you build on them

A platform offers generous API access, low fees and broad terms. Developers build businesses on it. Three years later the fees triple, the API is restricted and the terms are rewritten. The developers stay, because rebuilding on another platform costs more than the new terms.

What everyone sees

The change is described as maturation: the platform was subsidising growth, and now it needs to be sustainable. This is accurate as far as it goes, and it does not go as far as the economics go: the subsidy was not generosity but investment in a dependency that would later be monetised.

What is actually happening

Williamson described hold-up in transaction-cost economics: when one party has made relationship-specific investments, the other party can renegotiate terms because the cost of exiting exceeds the cost of the new terms. Parker, Van Alstyne and Choudary applied the framework to platform economics, where developers’ sunk investment in learning the API, building integrations and acquiring users on the platform constitutes a relationship-specific asset. The generous early terms are a rational acquisition strategy, not a long-term commitment.

Why it stays hidden

The strategy hides because the early terms are experienced as the baseline rather than as a temporary subsidy. Developers plan as though the current terms will persist, because the platform’s documentation says nothing about revision, and terms-of-service change clauses are not read as economic forecasts. By the time the terms change, the developer’s investment has created the very dependency that makes the new terms tolerable.