https://www.youngju.dev/blog 천천히 올바르게. AI Researcher & DevOps Engineer Youngju's tech blog. GPU/CUDA, LLM, MLOps, Kubernetes AI workloads, distributed training, and data engineering. ko fjvbn2003@gmail.com (Youngju Kim) fjvbn2003@gmail.com (Youngju Kim) Sat, 16 May 2026 00:00:00 GMT https://www.youngju.dev/blog/culture/2026-05-16-payment-apis-fintech-developer-2026-stripe-adyen-toss-payments-portone-square-mollie-deep-dive.en https://www.youngju.dev/blog/culture/2026-05-16-payment-apis-fintech-developer-2026-stripe-adyen-toss-payments-portone-square-mollie-deep-dive.en A comprehensive 2026 snapshot of the global, Korean, and Japanese payment API ecosystem. Stripe (still the leader), Adyen (European enterprise), Toss Payments / PortOne / KCP / Inicis (Korea), Square / Cash App, Razorpay (India), Mollie / Checkout.com / Braintree, Japan trio (GMO PG / PAY.JP / KOMOJU), plus the billing layer — Stripe Billing, Lago, OpenMeter, Orb, Metronome, Maxio — with webhook signature verification, idempotency keys, SCA, 3DS2, and consumption-based pricing in real code. Sat, 16 May 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) paymentsfintechstripeadyentoss-paymentsportoneiamportsquaremolliecheckout-combraintreerazorpaygmo-paymentpaypalstripe-billinglagoopenmeterorbmetronome2026deep-diveenglish https://www.youngju.dev/blog/culture/2026-05-16-payment-apis-fintech-developer-2026-stripe-adyen-toss-payments-portone-square-mollie-deep-dive.ja https://www.youngju.dev/blog/culture/2026-05-16-payment-apis-fintech-developer-2026-stripe-adyen-toss-payments-portone-square-mollie-deep-dive.ja 2026 年 5 月時点のグローバル・韓国・日本の決済 API エコシステムを一望します。Stripe（依然として 1 位）、Adyen（欧州エンタープライズ）、Toss Payments・PortOne・KCP・イニシス（韓国）、Square・Cash App、Razorpay（インド）、Mollie・Checkout.com・Braintree、日本の GMO Payment Gateway・PAY.JP・KOMOJU、さらに課金レイヤの Stripe Billing・Lago・OpenMeter・Orb・Metronome・Maxio。Webhook 署名検証、冪等性キー、SCA・3DS2、従量課金の実装まで実コードで解説します。 Sat, 16 May 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) paymentsfintechstripeadyentoss-paymentsportoneiamportsquaremolliecheckout-combraintreerazorpaygmo-paymentpaypalstripe-billinglagoopenmeterorbmetronome2026deep-dive日本語 https://www.youngju.dev/blog/culture/2026-05-16-payment-apis-fintech-developer-2026-stripe-adyen-toss-payments-portone-square-mollie-deep-dive https://www.youngju.dev/blog/culture/2026-05-16-payment-apis-fintech-developer-2026-stripe-adyen-toss-payments-portone-square-mollie-deep-dive 2026년 5월 기준 글로벌·한국·일본 결제 API 생태계를 한눈에 정리합니다. Stripe(여전한 1위)부터 Adyen(유럽 엔터프라이즈), Toss Payments·PortOne·KCP·이니시스(한국), Square·Cash App·Razorpay(인도)·Mollie(유럽)·Checkout.com·Braintree, 일본의 GMO Payment Gateway·PAY.JP·KOMOJU, 그리고 빌링 분야의 Stripe Billing·Lago·OpenMeter·Orb·Metronome·Maxio까지. 웹훅 서명 검증, 멱등 키, SCA·3DS2, 소비 기반 가격까지 실전 코드와 함께 다룹니다. Sat, 16 May 2026 00:00:00 GMT fjvbn2003@gmail.com (Youngju Kim) paymentsfintechstripeadyentoss-paymentsportoneiamportsquaremolliecheckout-combraintreerazorpaygmo-paymentpaypalstripe-billinglagoopenmeterorbmetronome2026deep-dive