What is Stripe.js primarily used for?

• A. A cloud data store for payment records.
• B. Stripe's foundational JavaScript library for building payment flows.
• C. A payment analytics service.
• D. A domain management tool.

Answer: (B)

Stripe.js is Stripe’s JavaScript library used on the client side to build payment flows. It lets you render Stripe Elements to securely collect card details and tokenize them so sensitive data never touches your server. This enables frontend payment interactions (like creating a payment method or confirming a payment) while keeping PCI scope lower. It’s the starting point for integrating payments in the browser and works with your server-side Stripe APIs to complete the transaction. The other options don’t describe this client-side, secure payment collection and flow-building role.