# Effects and Validation


Effect examples keep the computation fixed and change the handler.
This makes policy choices explicit: collect validation errors, log
each check, or stop at the first failure.

The source for this section lives under [examples/](https://github.com/kleisli-io/nix-effects/tree/main/examples).

## Walkthroughs

- [Handler-Swap Validation](/nix-effects/effect-examples/handlerSwapValidation): Run one validation computation with collecting, logging, and strict handlers.