Knowledge Base
Short explainers for payment gateway, issuing, website screening, eKYC, 3D Secure, ACS, and disputes.
Explore Knowledge Base →Knowledge Hub
Build the context for a better service discussion.
Knowledge Hub brings together evergreen explainers, common questions, and selected service perspectives.
Knowledge BaseFAQInsights & Updates
Explore resources
Choose the resource that matches your question.
FAQ
Answers to commercial, service-scope, regulatory-scope, and cooperation questions.
Read FAQ →Insights & Updates
Selected perspectives and service notes without a high-frequency news model.
Read Insights →Featured topics
Start with the concepts behind each service.
What is a Global Payment Gateway?
A gateway transports supported payment messages to contracted endpoints and returns statuses.
Read brief
A gateway transports supported payment messages to contracted endpoints and returns statuses. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →What is an Issuing Platform?
An issuing platform coordinates supported card-program configuration and lifecycle operations.
Read brief
An issuing platform coordinates supported card-program configuration and lifecycle operations. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →What is Website Screening?
Website screening reviews merchant websites for risk indicators relevant to payment operations.
Read brief
Website screening reviews merchant websites for risk indicators relevant to payment operations. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →What is eKYC?
eKYC coordinates digital onboarding, verification handoffs and exception review.
Read brief
eKYC coordinates digital onboarding, verification handoffs and exception review. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →What is 3D Secure?
3D Secure supports cardholder authentication in online card-not-present payments.
Read brief
3D Secure supports cardholder authentication in online card-not-present payments. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →What is an issuer-side ACS?
An ACS applies issuer policy for cardholder authentication within a 3D Secure flow.
Read brief
An ACS applies issuer policy for cardholder authentication within a 3D Secure flow. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →Requestor-side 3D Secure vs issuer-side ACS
A comparison of requestor-side integration and issuer-side authentication responsibilities.
Read brief
A comparison of requestor-side integration and issuer-side authentication responsibilities. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →What is Dispute Resolution?
Dispute workflows coordinate post-transaction cases, evidence and chargeback operations.
Read brief
Dispute workflows coordinate post-transaction cases, evidence and chargeback operations. Scope depends on the business model, applicable rules and confirmed service configuration.
View related service →Next step
Still have questions?
Contact Vellfi for a focused discussion about payment, issuing, authentication, onboarding review, or dispute service needs.