Serverless hosting involves hosting an application on a cloud provider's servers instead of on your own server. The application is divided into functions that are deployed to the provider and are called on when users interact with the application.
Developers only pay for periods of active user activity. There is no cost for periods of inactivity. No server management tasks need to be completed on the developer's part since the cloud provider takes care of those tasks.
Google Cloud is one provider of serverless hosting.
AWS Lambda is another provider of serverless hosting.
Serverless hosting is hosting an application through a cloud provider. Server management tasks are handed off to the provider. The provider only bills the developer for times when the application is actively used.