Testing the Mollie API

During the process of building your integration, it is important to properly test it. As briefly explained in our authentication guide, you can access the test mode of the Mollie API in two ways: by using the Test API key, or, if you’re using organization access tokens or app tokens, by providing the testmode parameter in your API request.

Any payments or other resources you create in test mode are completely isolated from your live mode data. Going back and forth between test and live mode is as easy as switching out the API key - or toggling the testmode parameter in case of the other authentication methods.

Test mode checkout screen

When creating payments or orders in test mode, the regular checkout screen will be replaced by a test mode checkout screen. Most test mode payment resources will feature a checkout URL just like in live mode, which then allows you to walk through the payment process without spending actual money. You can try out different payment statuses and see whether your integration handles it correctly.

For test mode recurring payments, the resource will not contain a checkout URL, because these payments are executed without any interaction of your customer. Instead, a changePaymentState URL is added, which allows you to set the final payment state for these payments.

Apart from the hosted payment pages and the fact that test mode payments are created instead of real ones, the Mollie API behaves almost identical in both environments. This includes calling your webhook. Just make sure to start using live mode when your site goes public, or your customers will get a free ride.