Dynamically update payment amounts

Learn how to modify total amounts when customers change their selections during checkout.

Update the amount of a Checkout Session or Payment Intent when customers change what they’re buying or how much they pay. Recalculate the totals on your server, and then update the amount of the PaymentIntent.

Common use cases

Add or remove add-ons (such as gift wrap or a warranty).
Select a different shipping method or delivery speed.
Add additional services or charges.
Apply or remove a discount code or store credit.

Security best practices

Recalculate amounts on your server. Don’t trust client-provided prices or totals.
Authorize the update based on your business rules (for example, enforce max quantities).
Only update Sessions that are active and not completed or expired.

Constraints and behavior

You can update the amount while the Payment Intent or Checkout Session is awaiting payment (for example, requires_payment_method or requires_confirmation).
After confirmation, you generally can’t increase the amount.

Update the client SDK
Client-side

When using Elements with the Checkout Sessions API, wrap client calls to your server in runServerUpdate so the checkout state and totals refresh.

checkout.js
import {loadStripe} from '@stripe/stripe-js';

// Optional: include beta flags if your integration requires them
const stripe = await loadStripe('pk_test_TYooMQauvdEDq54NiTphI7jx'
, {
  betas: ['custom_checkout_server_updates_1'],
});

const checkout = await stripe.initCheckout({
  elementsOptions: {/* ... */},
});

// Example: Add additional service using price_data
document
  .getElementById('add-service')
  .addEventListener('click', async () => {
    const updateOnServer = () =>
      fetch('/update-custom-amount', {
        method: 'POST',
        headers: {'Content-Type': 'application/json'},
        body: JSON.stringify({
          checkout_session_id: checkout.session().id,
          product_id: 'gift_wrap', // Server looks up actual price
        }),
      });

    const response = await checkout.runServerUpdate(updateOnServer);
    if (!response.ok) {
      // show error state
    }
  });

Create server endpoints
Server-side

Calculate amounts and validate inputs on your server. Then, you can update line_items with price_data to add ad-hoc charges.

注

Updating the line_items or price_data recalculates the Session total and taxes.

注