In a model-as-a-service arrangement, a provider hosts the model and customers use it over the internet, normally through an API. The provider handles the hardware, the serving software, scaling and updates, and the customer sends requests and pays, usually per token or by subscription. Model developers offer it directly, and cloud platforms and other companies also host models, including open-weight ones, in this way.
It lets teams start quickly, without buying chips or hiring infrastructure specialists, and it provides access to very capable models. Costs follow usage, which suits uneven or growing demand.
The trade-offs are dependence and exposure. Data is sent to a third party, the provider can change prices, limits or the model itself, outages affect your product, and heavy usage can end up costing more than running the model yourself. Contract terms about data use and retention matter.
Read the data and privacy terms, keep your code able to switch providers where possible, set spending limits and compare cost at your expected volume.