A 3-tier gateway uses a hosted payment page. This means when proceeding through an interactive site, people are redirected to a payment page hosted entirely in the e-commerce gateway’s environment.
This offers a high level of security and allows responses to be encrypted so that these gateways aren’t vulnerable to cardwashing attacks.
For security reasons, we limit the number of payment gateways we support, and these must be 3-tier gateways.
You can also choose EventsAir Pay, which offers high security without the need to re-direct to an external payment page.