To test the Mollie payment API on my localhost I needed a way to receive the webhook callback on my localhost. To be able to do this I needed a service to tunnel a public URL to localhost (my local machine, as opposed to a publicly accessible URL). Here are few examples of services that provide this service:
ngrok (free plan)
localtunnel (free)
These types of tools give you a publicly accessible URL that forwards the request to the localhost port, which can be used for the API callback URL while testing.
Adventures of a space monkey 
Hi,
can you explain how this works using ngrok?
More precisely, where to enter the public url from ngrok so that the Mollie callback comes in correctly.
I suspect this must be entered in Molli/API/Resource/Base.php ?
ANy help is appreciated.
Thx
Hi Marco.,
It is pretty straight forward. Just checkout the Ngrok homepage for instructions how to setup. I never used PHP to do the integration, so not much help there. It has also been a while since I did the integration, so not much help hoe to do it. Sorry mate.
Kind regards, nidkil