Which is better to use for Google Assistant? Actions SDK or JSON request response - dialogflow-es

Question

I have built multiple actions on Google Assistant using the JSON request and response V2 but I have heard that using Actions SDK for building actions specifically for Google Assistant should be preferred. I am confused whether to use Actions SDK or JSON request response?
For example - On this link, for every sample code there are two tabs, Node.js using Actions SDK and JSON using the JSON request response.
Which one should be preferred and in which scenarios?
Thanks!

Answer 1

Let's first look at what those tabs mean, and then discuss what your best approach should be.
node.js vs JSON tabs
The "node.js" tab shows what the code looks like using the actions-on-google library. For the most part, this library uses the same code if you're using either the Action SDK or using Dialogflow to implement. Where there are differences, the documentation does note how you have to handle them - this is particularly true when it comes to how you have to handle responses.
The "JSON" tab shows what the JSON would look like if you are not using the actions-on-google library and need to send JSON yourself. You might do this because you're using a language besides node.js, or you just want to know what the underlying protocol looks like.
The catch is that the JSON illustrated here is what would be used by the Action on Google JSON protocol. If you're using Dialogflow, then this JSON would be wrapped inside the payload.google field and there are a couple of other differences documented. So when generating JSON for a Dialogflow response, you should use this as a guide, but need to be aware of how it might differ.
What should you use?
What you use depends on what your needs are and what your goals are for developing.
If you are trying to develop something you intend to release, or might do so someday, and you are new to voice or bot interfaces, then you'll probably want to use Dialogflow - no matter what other choices you may make.
If you have your own Natural Language Processing (NLP) system, then you will want to use the Action SDK instead of Dialogflow. How you handle it (using the actions-on-google library or using JSON) will depend on how you need to integrate with that NLP.
If you're familiar with node.js, or want to learn it, then using the actions-on-google library is a good choice and that first tab will help you. (There are other choices. Dialogflow also has a dialogflow-fulfillment library, which is good if you want to be able to support the bot platforms it supports as well. The multivocal library has a more configuration-driven template approach to building a conversational backend that was designed to work with the Assistant and Dialogflow. Both of these illustrate how to do the same things that Google's documentation does.)
If you would rather use another language, you'll need to reference the JSON documentation because there are few complete libraries for these platforms. Your best bet would be to use Dialogflow with JSON. Dialogflow has some example JSON for how to apply the Google documentation you cite to their fulfillment protocol.
Summary
You should probably use Dialogflow.
If you can, use actions-on-google or another library.
If you have a need to use another language or want to use the JSON, be aware of the possible differences.