- Put all the action types, action types, and reducers for a given portion of the application into one file. This is known as the "ducks" structure, per https://github.com/erikras/ducks-modular-redux .
- Use a utility library like https://github.com/acdlite/redux-actions to generate action types and action creators for you
- Write middleware to manage common logic for your application such as API calls
- Skip writing action creators and declaring action constants, and just have components do `this.props.dispatch({type : "SOME_ACTION"})`.
I don't recommend the last approach, but it's _totally_ up to you, especially because what you regard as "too much boilerplate" is going to be a personal opinion. One person's "too much boilerplate" is another person's "explicit and easy to trace through the system".