Improve error messages in helpers

**Feature request**
It would be great to have serialization for controllers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_serialization` with default `false`.

The issue names no files, tests, or entry points. Start by locating controller handling, serialization logic, and configuration parsing; done means serialization is supported and the enable_serialization option defaults to false.

Written by the indexing model from the issue text.