So i'm looking at building an app to control my 3d printer. I will say something such as "tell me how long is left to print" the app will then go to my server which will issue a GET request to to the printer and and return a response which will be spoken over my smart speaker.
All the tutorials I have found mention Dialogflow which is a paid service.
Do I actually need it? I'm not afraid to get my hads dirty if it is just a case of slinging some code together.
Dialogflow is Google's platform used to create conversations, i'm not sure if it is 100% mandatory, but it is the way to go if you want to create things for Google Home.
Dialogflow has a free version which you can use for you own projects. You can sign-up for a free account at https://dialogflow.com/.
Here you can create an agent to create conversations. Using Dialogflow's Webhooks you could create a connection to your server (or code hosted in the cloud) to get the information from your 3d printer.
As Jordi said, Dialogflow is not a fully paid service. It is a service that has a generous free tier which is based around usage. For a personal project, you will be well under quota. Additionally, Dialogflow usage is entirely free if you're using Actions on Google.
To answer the question, you are not required to use Dialogflow if you do not want. Instead, you could use the Actions SDK, which is a barebones request/response system. However it does not include NLP or entity extraction, two main benefits of Dialogflow, which would mean you would need to do your own logic.
