What costs are involved with developing and/or releasing a Google Assistant App?
eg: Can you develop an app using DialogFlow and a backend (say Firebase) without having to pay while you learn?
What costs are involved with developing and/or releasing a Google Assistant App?
eg: Can you develop an app using DialogFlow and a backend (say Firebase) without having to pay while you learn?
First of all - you don't need to use Dialogflow or Firebase to develop your action. Both are suggested, but neither are required. You can use any NLP you want, or none at all if you use the Actions SDK (but you want an NLP). You can use any backend at all, including running it off your local machine and tunneling to it via ngrok, but you don't want to do that for production.
But, during development (and even during a light deployment before your action becomes massively popular and a stand-out hit), you have lots of solutions that will be free.
Dialogflow is free for use with the Google Assistant. Period. There is an Enterprise edition which offers additional services and support for a cost, but you won't need them. There are restrictions, but you won't bump into them until you hit 3 requests per second - which you shouldn't during development.
Firebase's free tier (the Spark Plan) is good for very simple experimentation, but once you start doing network calls to outside Google's network (if you are trying to call the network API for other services), you will be blocked. No worries! The "Blaze Plan" paid tier does require a way to bill you, but they don't start billing you until you get quite a bit of usage: 2 million function calls / month and similarly scaled usage of CPU, memory, and network. So even the "Blaze Plan" will be free during development (and for basic usage).
As an addition to shortQuestion's answer:
The free plan in Firebase should be enough if you're just using it for learning and developing apps for personal use. If you want to go a bit further you'll need to upgrade the plan.
You can sign up with a free trial for actions on Google to get 300$ of credits during a 12 month period which would be more than enough to do anything you want.
The costs of Firebase/Actions on Google on a higher plan aren't anything to worry about though, you'd be talking about a few cent per multiple hundred thousand requests.
For everything else yes it is, as long as you not using it already somewhere. You can for development also host your server local and use an ngrok tunnel as sever address for Dialogflow.