@funnelfox/billing

A modern TypeScript SDK for subscription payments with Primer Headless Checkout integration.

Features

🚀 Modern API: Clean, Promise-based interface with event-driven architecture
🔄 Dynamic Pricing: Update prices without page reload
🛡️ Type-Safe: Complete TypeScript definitions and type safety
🎯 Event-Driven: Handle success, errors, and status changes with ease
🔧 Robust: Built-in error handling, retries, and validation
📦 Lightweight: Minimal dependencies, browser-optimized
🎨 Headless Checkout: Full control over checkout UI with Primer Headless Checkout

Installation

Via CDN

<!-- Include Primer Headless Checkout SDK first -->
<script src="https://sdk.primer.io/web/v2.57.3/Primer.min.js"></script>
<link rel="stylesheet" href="https://sdk.primer.io/web/v2.57.3/Checkout.css" />

<!-- Include Funnelfox Billing SDK -->
<script src="https://unpkg.com/@funnelfox/billing@latest/dist/funnelfox-billing.min.js"></script>

Via NPM

npm install @funnelfox/billing @primer-io/checkout-web

If you are developing locally, install dev tooling for TypeScript builds/tests:

npm i -D @rollup/plugin-typescript ts-jest @types/jest

Then build:

npm run build

Quick Start

import { Billing } from '@funnelfox/billing';

await Billing.createCheckout({
  orgId: 'your-org-id',
  priceId: 'price_123',
  customer: {
    externalId: 'user_456',
    email: '[email protected]',
  },
  container: '#checkout-container',
});

API Reference

`configure(config)`

Configure global SDK settings.

import { configure } from '@funnelfox/billing';

configure({
  orgId: 'your-org-id', // Required
  baseUrl: 'https://custom.api', // Optional, defaults to https://billing.funnelfox.com
  region: 'us-east-1', // Optional, defaults to 'default'
});

Parameters:

config.orgId (string, required) - Your organization identifier
config.baseUrl (string, optional) - Custom API URL
config.region (string, optional) - Region, defaults to 'default'

`createCheckout(options)`

Creates a new checkout instance.

const checkout = await createCheckout({
  // Required
  orgId: 'your-org-id',
  priceId: 'price_123',
  customer: {
    externalId: 'user_456',
    email: '[email protected]',
    countryCode: 'US', // Optional
  },
  container: '#checkout-container',
  clientMetadata: { source: 'web' },
  cardSelectors: {
    // Custom card input selectors (optional, defaults to auto-generated)
    cardNumber: '#cardNumberInput',
    expiryDate: '#expiryInput',
    cvv: '#cvvInput',
    cardholderName: '#cardHolderInput',
    button: '#submitButton',
  },
  paypalButtonContainer: '#paypalButton', // Optional
  googlePayButtonContainer: '#googlePayButton', // Optional
  applePayButtonContainer: '#applePayButton', // Optional
  paymentMethodOrder: ['PAYMENT_CARD', 'PAYPAL', 'GOOGLE_PAY', 'APPLE_PAY'], // Optional

  // Callbacks (alternative to events)
  onSuccess: result => {
    /* ... */
  },
  onError: error => {
    /* ... */
  },
  onStatusChange: (state, oldState) => {
    /* ... */
  },
});

Parameters:

options.priceId (string, required) - Price identifier
options.customer (object, required)
- customer.externalId (string, required) - Your user identifier
- customer.email (string, required) - Customer email
- customer.countryCode (string, optional) - ISO country code
options.container (string, required) - CSS selector for checkout container
options.orgId (string, optional) - Org ID (if not configured globally)
options.clientMetadata (object, optional) - Custom metadata
options.cardSelectors (object, optional) - Custom card input selectors (defaults to auto-generated)
options.paypalButtonContainer (string, optional) - Container selector for PayPal button
options.googlePayButtonContainer (string, optional) - Container selector for Google Pay button
options.applePayButtonContainer (string, optional) - Container selector for Apple Pay button
options.paymentMethodOrder (array, optional) - Custom order for payment methods. Available values: 'PAYMENT_CARD', 'PAYPAL', 'GOOGLE_PAY', 'APPLE_PAY'. Defaults to ['PAYMENT_CARD', 'PAYPAL', 'GOOGLE_PAY', 'APPLE_PAY']
options.onInitialized (function, optional) - Initialized callback
options.onSuccess (function, optional) - Success callback
options.onError (function, optional) - Error callback
options.onStatusChange (function, optional) - State change callback

Returns: Promise<CheckoutInstance>

`createClientSession(params)`

Create a client session manually (for advanced integrations).

import { createClientSession } from '@funnelfox/billing';

const session = await createClientSession({
  priceId: 'price_123',
  externalId: 'user_456',
  email: '[email protected]',
  orgId: 'your-org-id', // Optional if configured
});

console.log(session.clientToken); // Use with Primer Headless Checkout
console.log(session.orderId);

Returns: Promise<{ clientToken: string, orderId: string, type: string }>

CheckoutInstance

Properties

id (string) - Unique checkout identifier
state (string) - Current state: initializing, ready, processing, completed, error
orderId (string) - Order identifier (available after initialization)
isDestroyed (boolean) - Whether checkout has been destroyed

Events

`'success'`

Emitted when payment completes successfully.

checkout.on('success', result => {
  console.log('Order ID:', result.orderId);
  console.log('Status:', result.status); // 'succeeded'
  console.log('Transaction:', result.transactionId);
});

`'error'`

Emitted when payment fails or encounters an error.

checkout.on('error', error => {
  console.error('Error:', error.message);
  console.error('Code:', error.code);
  console.error('Request ID:', error.requestId); // For support
});

`'status-change'`

Emitted when checkout state changes.

checkout.on('status-change', (newState, oldState) => {
  console.log(`${oldState} → ${newState}`);
  // States: initializing, ready, processing, action_required, completed, error
});

`'destroy'`

Emitted when checkout is destroyed.

checkout.on('destroy', () => {
  console.log('Checkout cleaned up');
});

Methods

`updatePrice(priceId)`

Updates the checkout to use a different price.

await checkout.updatePrice('price_yearly');

Note: Cannot update price while payment is processing.

`getStatus()`

Returns current checkout status.

const status = checkout.getStatus();
console.log(status.id); // Checkout ID
console.log(status.state); // Current state
console.log(status.orderId); // Order ID
console.log(status.priceId); // Current price ID
console.log(status.isDestroyed); // Cleanup status

`destroy()`

Destroys the checkout instance and cleans up resources.

await checkout.destroy();

`isReady()`

Check if checkout is ready for payment.

if (checkout.isReady()) {
  console.log('Ready to accept payment');
}

`isProcessing()`

Check if payment is being processed.

if (checkout.isProcessing()) {
  console.log('Payment in progress...');
}

Complete Example

<!DOCTYPE html>
<html>
  <head>
    <title>Funnelfox Checkout</title>
    <script src="https://sdk.primer.io/web/v2.57.3/Primer.min.js"></script>
    <link
      rel="stylesheet"
      href="https://sdk.primer.io/web/v2.57.3/Checkout.css"
    />
    <script src="https://unpkg.com/@funnelfox/billing@latest/dist/funnelfox-billing.min.js"></script>
  </head>
  <body>
    <div id="price-selector">
      <button onclick="selectPrice('price_monthly')">Monthly - $9.99</button>
      <button onclick="selectPrice('price_yearly')">Yearly - $99.99</button>
    </div>

    <div id="checkout-container"></div>

    <script>
      let currentCheckout = null;

      // Configure SDK once
      Billing.configure({
        orgId: 'your-org-id',
      });

      async function selectPrice(priceId) {
        try {
          if (currentCheckout && currentCheckout.isReady()) {
            // Update existing checkout
            await currentCheckout.updatePrice(priceId);
          } else {
            // Destroy old checkout if exists
            if (currentCheckout) {
              await currentCheckout.destroy();
            }

            // Create new checkout
            currentCheckout = await Billing.createCheckout({
              priceId: priceId,
              customer: {
                externalId: generateUserId(),
                email: getUserEmail(),
              },
              container: '#checkout-container',
            });

            // Handle success
            currentCheckout.on('success', result => {
              alert('Payment successful!');
              window.location.href = '/success?order=' + result.orderId;
            });

            // Handle errors
            currentCheckout.on('error', error => {
              alert('Payment failed: ' + error.message);
            });

            // Track state changes
            currentCheckout.on('status-change', state => {
              console.log('Checkout state:', state);
            });
          }
        } catch (error) {
          console.error('Checkout error:', error);
          alert('Failed to initialize checkout');
        }
      }

      function generateUserId() {
        return 'user_' + Math.random().toString(36).substr(2, 9);
      }

      function getUserEmail() {
        return '[email protected]'; // Get from your auth system
      }
    </script>
  </body>
</html>

Error Handling

The SDK provides specific error classes for different scenarios:

import {
  ValidationError,
  APIError,
  PrimerError,
  CheckoutError,
  NetworkError,
} from '@funnelfox/billing';

try {
  const checkout = await createCheckout(config);
} catch (error) {
  if (error instanceof ValidationError) {
    // Invalid input
    console.log('Field:', error.field);
    console.log('Value:', error.value);
    console.log('Message:', error.message);
  } else if (error instanceof APIError) {
    // API error
    console.log('Status:', error.statusCode);
    console.log('Error Code:', error.errorCode); // e.g., 'double_purchase'
    console.log('Error Type:', error.errorType); // e.g., 'api_exception'
    console.log('Request ID:', error.requestId); // For support
    console.log('Message:', error.message);
  } else if (error instanceof PrimerError) {
    // Primer SDK error
    console.log('Primer error:', error.message);
    console.log('Original:', error.primerError);
  } else if (error instanceof CheckoutError) {
    // Checkout lifecycle error
    console.log('Phase:', error.phase);
    console.log('Message:', error.message);
  } else if (error instanceof NetworkError) {
    // Network/connectivity error
    console.log('Network error:', error.message);
    console.log('Original:', error.originalError);
  }
}

Common Error Codes

double_purchase - User already has an active subscription
invalid_price - Price ID not found
invalid_customer - Customer data validation failed
payment_failed - Payment processing failed

TypeScript Support

The SDK includes comprehensive TypeScript definitions:

import {
  configure,
  createCheckout,
  CheckoutInstance,
  PaymentResult,
  CheckoutConfig,
  PaymentMethod,
} from '@funnelfox/billing';

// Configure
configure({
  orgId: 'your-org-id',
});

// Create checkout with type safety
const checkout: CheckoutInstance = await createCheckout({
  priceId: 'price_123',
  customer: {
    externalId: 'user_456',
    email: '[email protected]',
    countryCode: 'US',
  },
  container: '#checkout',
  clientMetadata: {
    source: 'web',
    campaign: 'summer-sale',
  },
  paymentMethodOrder: [
    PaymentMethod.PAYPAL,
    PaymentMethod.PAYMENT_CARD,
    PaymentMethod.GOOGLE_PAY,
    PaymentMethod.APPLE_PAY,
  ],
});

// Type-safe event handlers
checkout.on('success', (result: PaymentResult) => {
  console.log('Order:', result.orderId);
  console.log('Status:', result.status);
  console.log('Transaction:', result.transactionId);
});

Advanced Usage

Using Callbacks Instead of Events

const checkout = await createCheckout({
  priceId: 'price_123',
  customer: {
    externalId: 'user_456',
    email: '[email protected]',
  },
  container: '#checkout',

  // Callback style (alternative to .on() events)
  onSuccess: result => {
    console.log('Success!', result.orderId);
  },
  onError: error => {
    console.error('Error!', error.message);
  },
  onStatusChange: (newState, oldState) => {
    console.log(`${oldState} → ${newState}`);
  },
});

Custom Card Input Selectors

By default, the SDK automatically generates card input elements. You can provide custom selectors if you want to use your own HTML structure:

const checkout = await createCheckout({
  priceId: 'price_123',
  customer: {
    externalId: 'user_456',
    email: '[email protected]',
  },
  container: '#checkout',

  // Custom card input selectors
  cardSelectors: {
    cardNumber: '#my-card-number',
    expiryDate: '#my-expiry',
    cvv: '#my-cvv',
    cardholderName: '#my-cardholder',
    button: '#my-submit-button',
  },

  // Custom payment method button containers
  paypalButtonContainer: '#my-paypal-button',
  googlePayButtonContainer: '#my-google-pay-button',
  applePayButtonContainer: '#my-apple-pay-button',
});

Custom Payment Method Order

You can customize the order in which payment methods are displayed to your customers:

const checkout = await createCheckout({
  priceId: 'price_123',
  customer: {
    externalId: 'user_456',
    email: '[email protected]',
  },
  container: '#checkout',

  // Customize payment method order
  paymentMethodOrder: ['PAYPAL', 'GOOGLE_PAY', 'APPLE_PAY', 'PAYMENT_CARD'],
});

Available payment methods:

'PAYMENT_CARD' - Credit/debit card payment
'PAYPAL' - PayPal payment
'GOOGLE_PAY' - Google Pay payment
'APPLE_PAY' - Apple Pay payment

By default, payment methods are shown in the order: Card, PayPal, Google Pay, Apple Pay. You can reorder them to match your business priorities or regional preferences.

Manual Session Creation

For advanced integrations where you want to control the Primer Headless Checkout directly:

import { createClientSession } from '@funnelfox/billing';
import { Primer } from '@primer-io/checkout-web';

// Step 1: Create session
const session = await createClientSession({
  priceId: 'price_123',
  externalId: 'user_456',
  email: '[email protected]',
  orgId: 'your-org-id',
});

// Step 2: Use with Primer Headless Checkout directly
const headlessCheckout = await Primer.createHeadless(session.clientToken, {
  paymentHandling: 'MANUAL',
  apiVersion: '2.4',
  onTokenizeSuccess: async (paymentMethodTokenData, handler) => {
    // Your custom payment logic...
    // Call your payment API with paymentMethodTokenData.token
    handler.handleSuccess();
  },
});

await headlessCheckout.start();

Browser Support

Chrome 60+
Firefox 55+
Safari 12+
Edge 79+

Examples

See the examples directory for more complete examples:

Basic Checkout - Simple checkout integration

Name		Name	Last commit message	Last commit date
Latest commit History 27 Commits
examples		examples
src		src
tests		tests
.babelrc		.babelrc
.editorconfig		.editorconfig
.eslintrc.js		.eslintrc.js
.gitignore		.gitignore
.npmignore		.npmignore
.prettierignore		.prettierignore
.prettierrc		.prettierrc
CHANGELOG.md		CHANGELOG.md
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md
jest.config.js		jest.config.js
package-lock.json		package-lock.json
package.json		package.json
rollup.config.js		rollup.config.js
tsconfig.jest.json		tsconfig.jest.json
tsconfig.json		tsconfig.json

License

adaptyteam/funnelfox-billing-js

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@funnelfox/billing

Features

Installation

Via CDN

Via NPM

Quick Start

API Reference

configure(config)

createCheckout(options)

createClientSession(params)

CheckoutInstance

Properties

Events

'success'

'error'

'status-change'

'destroy'

Methods

updatePrice(priceId)

getStatus()

destroy()

isReady()

isProcessing()

Complete Example

Error Handling

Common Error Codes

TypeScript Support

Advanced Usage

Using Callbacks Instead of Events

Custom Card Input Selectors

Custom Payment Method Order

Manual Session Creation

Browser Support

Examples

License

About

Resources

License

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`configure(config)`

`createCheckout(options)`

`createClientSession(params)`

`'success'`

`'error'`

`'status-change'`

`'destroy'`

`updatePrice(priceId)`

`getStatus()`

`destroy()`

`isReady()`

`isProcessing()`

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