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Accept a payment from a customer who hasn’t paid through PayNext before. The SDK handles payment method collection, validation, and 3D Secure authentication automatically.

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When to Use

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Prerequisites

Before accepting payments:
  1. PayNext account with API keys (Testing & Sandbox)
  2. Processor connected in Dashboard → Integrations
  3. Plan created in Dashboard → Plans (defines amount and currency)
  4. Payment methods enabled in Dashboard → Checkout

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Integration

Follow the SDK Quickstart to:
1

Create a client session

Call POST /client-session from your server with customer email and plan ID.
2

Mount the SDK

Initialize checkout with the session id as clientToken.
3

Handle the result

Use onCheckoutComplete and onCheckoutFail callbacks.
The SDK Quickstart includes complete code examples for Next.js and vanilla TypeScript, plus optional optimizations like preloading.
Using a one-off plan with a variable amount? Add a plan.price to the client session to override the plan’s amount for this checkout. See Custom Pricing.

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What Happens Next

After a successful first payment:
  • Customer created in PayNext with saved payment method
  • Payment method stored securely for future charges
  • Subscription started (if using a recurring plan)
For subsequent charges, use Charge Returning Customers to leverage the saved payment method.