Through the API

Affiliate program for Mollie

With Mollie, your server reports the sale to Meritt through the API, in three calls, as soon as Mollie confirms the payment. Attribution and the ledger are the same as for Stripe.

What Meritt reads

• What your server sends us: POST /v1/conversions to report the sale, POST /v1/identify to tie a customer to a visit, POST /v1/conversions/reverse for a refund. A sale sent twice is counted once.
• The click, which you store in metadata at checkout.
• The customer id, which ties later payments to the same affiliate.

Worth knowing

• According to Mollie, the webhook carries a single parameter, id: your server fetches the payment to learn its status before reporting it to us.

Setting it up

1. Create an API key under Payment system; the calls are documented on the same screen.
2. At checkout, read the click cookie on your domain and store it in metadata.
3. When Mollie sends you a webhook whose fetched payment is paid, call POST /v1/conversions with the amount, the currency, the click and the customer id.
4. On a webhook whose fetched refund is refunded, call POST /v1/conversions/reverse with the payment reference.

How long it takes

One key, and two calls added to your webhook handling.

Questions

Mollie documentation checked on October 19, 2026: docs.mollie.com › webhooks, docs.mollie.com › create payment, docs.mollie.com › create subscription