Paying online in Korea, you'll often hit the checkout bouncing to another screen, prompts to set up 'ISP secure payment' or 'AnsimClick,' or a foreign card that either doesn't appear or fails authorization. It's not that Korean payments are broken, but that several layers overlap.
The triangle: shop + PG + card/bank
Since shops find it hard to integrate directly with card companies, a payment gateway (PG) usually sits in the middle. When you see 'KG Inicis, KCP, or Toss Payments' at checkout, it's because you've been handed off to that PG's payment module to process card approval and authentication.
Why authentication feels doubled
- Card authentication: 'is this really the cardholder using the card?' — services like ISP secure payment and AnsimClick (MPI)
- Identity verification: 'is this person the real user?' — ARS or SMS verification per service or simple-pay app. These are separate, so you may be asked for both
Tips for foreign cards
Foreign-issued cards sometimes don't appear as a payment option or get blocked at the 3D Secure (Visa/Mastercard verification) step. Where possible, use merchants that explicitly support foreign cards, or PayPal and global checkout, and if you're staying long-term, the easiest path is to get a Korean card and register it in Toss, Naver Pay, or KakaoPay.
Korea online payments explained: PG, card auth, ID verification, and foreign-card fixes