I want to use Dialogflow fulfillment to connect to an external webservice / API. One way of doing that is to use the custom webhook feature (not the inline web hook). However, when using the custom web hook it seems that you are limited to creating just one even though you may have many intents and you may want to call many endpoints. Is there a way to link to more custom webhooks (API endpoints)?
If you can only set up one web hook then your webserivce will always receive a Post request from Dialogflow and will then need to interpret the body of the request i.e. based on the intent parameter. Just wondering is there a better way to work with REST webservices with Dialogflow.
The other potential option is to use the inline web hook and then put logic in there to call specific endpoints, however, that might get a bit messy.
You can only setup one fulfillment that will handle the processing for all the Intents you've enabled. This can be either the built-in one through the fulfillment editor or at a webhook URL you specify.
That webhook is expected to delegate the actual processing to an Intent Handler of some sort. The Dialogflow node.js fulfillment library has a way to register what handler you want for each Intent name, or you can switch on the Intent name, the Action name, or any other field provided to you in your code.
In the library, you'll typically make the REST calls from an appropriate Intent handler which will take the parameters provided and craft the call. If you are using Javascript, make sure you are handling the call asynchronously and return a Promise.
I recommend a webhook because it gives you more control than the inline editor does. The inline editor is really just a webhook under the covers using Firebase Cloud Functions. Even putting it yourself in a Cloud Function gives you better control over it.
There may be costs depending where you host it, however Firebase has a free tier that is sufficient for testing and light operation. Once your Action is published, you are also eligible for a monthly cloud credit from Google.