Payment gateway detection is particularly valuable for sales and business intelligence. If you sell payment processing services, integrate with specific gateways, or analyze ecommerce trends, knowing which payment providers a website uses gives you actionable insights. This guide covers how to detect Stripe, PayPal, Klarna, Mollie, and other major payment gateways.
Script-Based Detection
Most payment gateways require loading a JavaScript SDK on the checkout page. These scripts are the most reliable detection signal:
- Stripe: Loads
js.stripe.com/v3/for Stripe Elements and Checkout. TheStripeJavaScript global confirms its presence. - PayPal: The PayPal SDK loads from
www.paypal.com/sdk/js. Older integrations usewww.paypalobjects.com. - Klarna: Detected via scripts from
js.klarna.comorx.klarnacdn.net. Klarna also injects badge and messaging widgets. - Mollie: Loads components from
js.mollie.com. Often detected alongside WooCommerce or other ecommerce platforms. - Square: Identified by scripts from
web.squarecdn.comand theSqPaymentFormglobal.
HTML and Form Patterns
Payment gateways also leave traces in the HTML, particularly on checkout pages. Stripe renders its card input inside an iframe from js.stripe.com. PayPal checkout buttons appear within iframes from paypal.com. Buy-now-pay-later providers like Klarna and Afterpay inject promotional messaging widgets throughout product pages.
These HTML patterns are especially useful for detecting payment providers that load their scripts dynamically only when the user initiates checkout. A static page scan may miss these, but a full browser-based scan will catch them.
Why Payment Detection Matters
For fintech companies and payment service providers, understanding the competitive landscape is essential. Knowing that a store uses Stripe tells you about their developer sophistication. Seeing PayPal alongside a traditional gateway suggests they offer multiple checkout options. Detecting buy-now-pay-later services reveals their approach to conversion optimization.
For ecommerce agencies, payment gateway information helps scope migration projects and propose better alternatives based on the client's current setup.
Automated Payment Gateway Detection
WhatStack detects all major payment gateways as part of its full technology scan. The detection engine analyzes script URLs, HTML patterns, and JavaScript globals to identify Stripe, PayPal, Klarna, Mollie, Square, Adyen, and many more. Results include the payment category classification, making it easy to filter for payment-specific technologies. Try scanning an ecommerce site with the WhatStack scanner to see its complete payment stack.