Security comes first at Mollie, and the Mollie API is no exception. Mollie guarantees a safe yet easy-to-use API in a number of key ways described below.

Connecting to the Mollie API

To connect to the Mollie API, an HTTPS connection with at minimum TLS1.2 is required. Requests are authenticated using API keys. This follows the industryโ€™s best practices.

End-to-end safety on the transport level is guaranteed by the HTTPS-requirement, no need to encrypt the data itself again. We only support TLS 1.2 (or higher). Connection is not possible when using a lower version.

HTTPS mitigates packet sniffing and timing attacks, and replay attacks. Thanks to HTTPS, data exchanged between Mollie and the merchant is protected and guaranteed to be authentic. HTTPS implements hashed signatures, nonces, and other tried and tested cryptographic safeties.

Man-in-the-middle attacks are prevented by strictly checking the HTTPS certificate used on If the client detects a fake certificate โ€” for example because of a hacked DNS-server โ€” no connection will be established.

Sensitive information

Any sensitive payment information entered by your customer on our platform is stored securely. Our credit card platform specifically is PCI DSS certified. Your own website does not require any form of certification, since we handle the entire transaction for you.

What about the webhooks?

The Mollie API webhooks never contain sensitive information. Instead, webhooks will only signal to your server that an update is ready to be fetched from the Mollie API, after which you are expected to fetch the object yourself in order to retrieve the updated details โ€” for example the updated status of a payment. Since your API call to us takes place over HTTPS, all the earlier-mentioned security guarantees stay in effect.

Reporting vulnerabilities

If you believe you have found a security issue in our product or service, please notify us as soon as possible by emailing us at [email protected]. For more information on this program, please refer to our Responsible Disclosure Policy.