Move Mollie back to Payments API instead of Orders API

[martijnvdbrug]

Is your feature request related to a problem? Please describe. The Mollie docs mention that they do not recommend moving to the orders API anymore. Something we did 1,5 year ago in this issue.

The main issue with the Payments API was that it does not support some payment methods like Klarna. The docs state that this will be implemented somewhere this year. We should not move to the Payments API before these are implemented

From the Mollie Discord:

While we will continue to support the Orders API for now, we recommend using the Payments API. We will focus our development efforts on the Payments API, so any new features will be focused on this endpoint.

If you are building a new integration, we strongly recommend to use the Payments API. We are working on making the missing payment methods (like Klarna) available on the Payments API this year. If you cannot wait for this, it is no problem to still integrate the Orders API.

Existing integrations can continue to use the Orders API. While we may decide to officially deprecate the API in the future, we have not made such a decision. If and when we do, we will of course provide ample time for our customers to upgrade. Also note that the new and shiny features will probably not be available on the Orders API.

Describe the solution you'd like

When Mollie implements the missing payment methods in the Payments API, there really is no reason to use the Orders API anymore, which simplifies the code on our side quite a bit.

Pro's

• We don't have to update orders in Mollie when a checkout is called twice. We just create a new payment.
• Arbitrary refund amounts don't have to be linked to order lines anymore. We can just refund an amount from a given payment
• No more rounding workarounds. Mollie uses order line rounding where Vendure uses unit rounding
• Architecture: It makes sense to have Vendure responsible for its order lines and corresponding amounts and taxes, and Mollie just for any arbitrary amount to be paid, calculated by Vendure. With the Orders API we have to replicate a Vendure order in Mollie, and calculations (like taxes) have to match.

Con's I can't see any, but I would like to ask any Mollie users: What do you use from the Mollie Orders API that is not supported by the Payments API?

[casperiv0]

I'm not seeing any drawbacks/cons to this either. Makes the entire logic much easier to understand too. I've asked our team if we use any of those services that are coming later this year in Mollie (Updating this comment once I have that information.)

[martijnvdbrug]

@casperiv0 Thanks for the feedback! We have several clients who are using the pay-later (e.g. Klarna and others) methods, so I propose if we move back to the payments API, we only do so after the Payments API supports those methods as well.