Where there is a need for more customization and control over the checkout experience, a headless version of Primer’s Universal Checkout is available.
You can use Headless Universal Checkout with your UI, giving you more flexibility and allowing you to move faster when making design changes, while still having Universal Checkout capture sensitive PCI card data or other form data.
If you're looking for a simpler way of integrating Universal Checkout, consider integrating our Drop-In checkout.
Not all payment methods are currently compatible with Headless Checkout.
Please refer to this table to learn more about the payment methods available for Headless Checkout.
Before you start
Before you start, make sure:
- you are ready to process a payment
- Universal Checkout is properly configured in the dashboard
Create a client session
A client session is the starting point for integrating payments at Primer. You can attach any data associated with the order
to your client session.
Creating a client session provides you with a client token, a temporary key used to initialize the Universal Checkout.
The information you include in the client session is used in the Dashboard:
- to conditionally route payments with Workflows
- to activate payment methods and other features in Universal Checkout
So pass as much information as you can!
Generate an API key
Requests to our API are authenticated using an API key in the X-Api-Key
header. Create an API key by visiting the developer page of the Primer Dashboard.
Make sure to set the following scopes for your API Key:
client_tokens:write
transactions:authorize
Make a client session request
On your server, create a client session with POST/client-session
.
Make sure to pass at least the following data:
Field | Description |
---|---|
Your reference for the payment. Make sure to keep track of orderId - you will later receive updates to the payment via Webhooks. The payment will contain the orderId specified in the client session. | |
The three-letter currency code in ISO 4217 format. e.g. use USD for US dollars. | |
The details of the line items of the order. |
The body of a successful response contains a clientToken that you will use to initialize the Universal Checkout.
Here is how the client session request to the Primer API should look like:
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curl --location --request \ POST 'https://api.sandbox.primer.io/client-session' \ --header 'X-Api-Key: <YOUR_API_KEY>' \ --header 'X-Api-Version: 2.2' \ --header 'Content-Type: application/json' --data '{ "orderId": "<YOUR_ORDER_ID>", "currencyCode": "GBP", "amount": 5000, "order": { "lineItems": [{ "itemId": "shoes-123", "amount": 2500, "quantity": 2 }], "countryCode": "GB", } }' # Here is a (heavily truncated) example response { "clientToken": "THE_CHECKOUT_SESSION_TOKEN", "clientExpirationDate": "2022-03-08T14:00:00Z", "orderId": "<YOUR_ORDER_ID>", "currencyCode": "GBP", "amount": 5000, "order": { "lineItems": [{ "itemId": "shoes-123", "amount": 2500, "quantity": 2 }], "countryCode": "GB", }}
To use new Workflows and all of its exciting features, make sure to pass the following header in your API request:
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Legacy-Workflows: false
See this migration guide for more information.
Get Started
Primer Headless Universal Checkout works in a simple way:
- 1Get a
clientToken
from your server - 2Start Primer Headless Universal Checkout with the client token
- 3Primer Headless Universal Checkout will then return the
available payment methods
for the session initiated. Those payment methods that have been configured in the Dashboard and whose conditions match the current client session will be returned. - 4You show the user the list of available payment methods.
- 5When the user selects a payment method, show its UI to enable the user to enter their credentials. Depending on the payment method, you will have to either ask the SDK to render it, or build the UI yourself.
- 6Primer's Headless Universal Checkout will then create a payment for you and manage its lifecycle. You will receive a confirmation of payment with a callback to indicate the checkout flow has completed.
Step 1. Install the SDK
With npm
Our Web SDK is available on npm under the name @primer-io/checkout-web
.
This package includes TypeScript definitions.
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# With yarnyarn add @primer-io/checkout-web # With npmnpm install --save @primer-io/checkout-web
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import { Primer } from '@primer-io/checkout-web' Primer.showUniversalCheckout(clientToken, { /* Options */})
- The npm package only works if used alongside a bundler such as Webpack or Parcel. If you're directly writing JavaScript using
script
tag, please use our CDN instead. - As of today, the npm package does not work in a server environment. If you are using Next.js, Gatsby, or a similar framework, make sure the
Primer
functions are called on the client side, or use our CDN instead.
With our CDN
Include the Primer.min.js
script and the Checkout.css
stylesheet on the page where you want to render the Checkout.
Make sure to pass the proper version in the URL.
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<link rel="stylesheet" href="https://sdk.primer.io/web/v2.30.0/Checkout.css" /><script src="https://sdk.primer.io/web/v2.30.0/Primer.min.js" crossorigin="anonymous"></script>
The Primer.min.js
will add the Primer
object to the global scope:
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const { Primer } = window Primer.showUniversalCheckout(clientToken, { /* Options */})
Step 2: Initialize Primer’s Headless Universal Checkout
Generate a client token
Request a client token from your backend by creating a client session.
Check our guide on how to create a client session here.
Remember that based on your client token different payment methods will be available for display.
Configure Headless Universal Checkout
Once you have a client token, initialize Primer’s headless checkout with Primer.createHeadless(clientToken)
.
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const headless = await Primer.createHeadless(clientToken)
Then, configure headless checkout by calling headless.configure(options)
. Make sure to implement at least the following callbacks:
onAvailablePaymentMethodsLoad(paymentMethodTypes)
returns the available payment methods for the client session. Use it to render a list of payment methods.onCheckoutComplete(data)
is called when the payment has been successfully completed. It returns a reference to the payment.onCheckoutFail(error, data, handler)
is called if the payment fails to be created or processed.
Payment methods are added and configured through your Primer Dashboard. onAvailablePaymentMethodsLoad
will return the payment methods
whose conditions match the current client session.
Finally, call headless.start()
to retrieve the list of payment methods, and start the checkout flow.
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await headless.start()
Here is a full example to configure and start Headless Universal Checkout:
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window.addEventListener('load', onLoaded) async function onLoaded() { // Create a client session via your backend const clientSession = await fetch('/client-session', { method: 'post', headers: { 'Content-Type': 'application/json' }, }).then(data => data.json()) const { clientToken } = clientSession const { Primer } = window // Create an instance of the headless checkout const headless = await Primer.createHeadless(clientToken) // Configure headless await headless.configure({ onAvailablePaymentMethodsLoad(paymentMethods) { // Called when the available payment methods are retrieved for (const paymentMethod of paymentMethods) { // `type` is a unique ID representing the payment method const { type, managerType } = paymentMethod switch (managerType) { case 'CARD': { // Configure your card form (see Step 4.a) // await configureCardForm(paymentMethod); break } case 'NATIVE': { // Render the native payment method button (see Step 4.b) // Relevant for PayPal, Apple Pay and Google Pay // configureNativeButton(paymentMethod); break } case 'REDIRECT': { // Handle redirect payment methods (see Step 4.c) // configureRedirectPaymentMethod(paymentMethod); break } // More payment methods to follow } } }, onCheckoutComplete({ payment }) { // Notifies you that a payment was created // Move on to next step in your checkout flow: // e.g. Show a success message, giving access to the service, fulfilling the order, ... console.log('onCheckoutComplete', payment) }, onCheckoutFail(error, { payment }, handler) { // Notifies you that the checkout flow has failed and a payment could not be created // This callback can also be used to display an error state within your own UI. // ⚠️ `handler` is undefined if the SDK does not expect anything from you if (!handler) { return } // ⚠️ If `handler` exists, you MUST call one of the functions of the handler // Show a default error message return handler.showErrorMessage() }, }) // Start the headless checkout await headless.start() console.log('Headless Universal Checkout is loaded!')}
See more options and events in the SDK API Reference
Step 3: Show available payment methods
When the checkout is done initializing, the callback onAvailablePaymentMethodsLoad
is invoked. Use this event to show the list of payment methods to the user:
Some payment methods such as Google Pay, Apple Pay, and PayPal require Primer to manage their payment method button.
For the others, you have full control over how the payment method button should be presented. To assist you, Primer exposes the
AssetsManager
that enables you to retrieve the logo and main colors attached to each payment method.
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// getAssetsManager() is only available once Headless Checkout has been fully initializedconst assetsManager = headless.getAssetsManager() const { iconUrl, paymentMethodName, backgroundColor } = await assetsManager.getPaymentMethodAsset('ADYEN_IDEAL') // ADYEN_IDEAL comes from `paymentMethod.type`
The assets manager is only available once onAvailablePaymentMethodsLoad
has been called.
Step 4: Handle payment method selection
Headless Universal Checkout enables you to create any UI that suits your needs, using the components and data we provide.
Step 4.a: Handle cards
When PAYMENT_CARD
is available as a payment method and provided via onAvailablePaymentMethodsLoad
, build your card form using Primer input elements.
Get started by creating a payment method manager for cards.
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const cardManager = await headless.createPaymentMethodManager('PAYMENT_CARD')
Show card components
First, prepare containers in the DOM for the Primer hosted inputs. You would need three containers for the card number, the expiry date, and the CVV.
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const container = document.getElementById('my-container') const cardNumberInputId = 'checkout-card-number-input'const cardNumberInputEl = document.createElement('div')cardNumberInputEl.setAttribute('id', cardNumberInputId) const cardExpiryInputId = 'checkout-card-expiry-input'const cardExpiryInputEl = document.createElement('div')cardExpiryInputEl.setAttribute('id', cardExpiryInputId) const cardCvvInputId = 'checkout-card-cvv-input'const cardCvvInputEl = document.createElement('div')cardCvvInputEl.setAttribute('id', cardCvvInputId) container.append(cardNumberInputEl, cardExpiryInputEl, cardCvvInputEl)
Then, create the hosted card inputs:
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const { cardNumberInput, expiryInput, cvvInput } = cardManager.createHostedInputs()
Finally, render your inputs into the relevant containers:
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await Promise.all([ cardNumberInput.render(cardNumberInputId, { placeholder: '1234 1234 1234 1234', ariaLabel: 'Card number', }), expiryInput.render(cardExpiryInputId, { placeholder: 'MM/YY', ariaLabel: 'Expiry date', }), cvvInput.render(cardCvvInputId, { placeholder: '123', ariaLabel: 'CVV', }),])
Customize card components
Card components are rendered with individual iframes in order to remain PCI-L1 compliant. One key consequence is that the CSS of your page will not be propagated to the card components. This includes color, and font.
Pass a style
object to the render
function to configure colors and font options.
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const style = { input: { base: { height: 'auto', border: '1px solid rgb(0 0 0 / 10%)', borderRadius: '2px', padding: '12px', boxShadow: '0 4px 8px 0 rgba(0,0,0,0.2)', }, },} cardNumberInput.render(cardNumberInputId, { placeholder: '1234 1234 1234 1234', ariaLabel: 'Card number', style,})
Check the "Styling Inputs" section of the Customize Universal Checkout guide to learn how to adapt the style to your requirements.
Reset card form
If needed, the card form can be cleared by calling reset()
:
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cardManager.reset()
Remove card elements
Call removeHostedInputs()
to remove the hosted card input fields from the DOM:
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cardManager.removeHostedInputs()
Detect card type
When the user enters the card credentials, Headless Universal Checkout automatically detects the possible types of the card.
Listen to the callback onCardMetadataChange
on the card manager to receive the type of card.
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const cardManager = await headless.createPaymentMethodManager('PAYMENT_CARD', { onCardMetadataChange({ type }) { console.log('Card type: ', type) },})
Capture cardholder name
You are free to render the cardholder name input however you want.
As the user enters their cardholder name, call setCardholderName(cardholderName)
to pass the cardholder name to the cardManager
:
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cardholderNameInput.addEventListener('change', e => { cardManager.setCardholderName(e.target.value)})
If the cardholder name is required, its content will be validated by Headless Universal Checkout.
You can specify whether the cardholder name is required by setting an option when initializing Headless Universal Checkout:
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await headless.configure({ card: { cardholderName: { required: true, }, },})
Handle input errors
The event change
, available on each input, reacts to input changes. This returns if the input is valid or not, and the error type.
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cardNumberInput.addEventListener('change', (...args) => { console.log('cardNumberInput changed', ...args)})
Validate and Submit
When the user submits the card information, follow the following flow:
- First, validate all the inputs using the
validate()
function that does basic validations on the hosted inputs. - Then, submit the validated data using the
submit()
function. This triggers the payment creation.
For example, if the user clicks submit, you can handle it as follows:
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submitButton.addEventListener('click', async () => { // Validate your card input data const { valid } = await cardManager.validate() if (valid) { // Submit the card input data to Primer for tokenization await cardManager.submit() } }})
Calling submit()
triggers the creation and handling of the payment.
- If
onCheckoutComplete
is called, show a success message and reset the inputs. - If
onCheckoutFail
is called, show a failure message and allow the customer to try again with the same details.
Prepare 3DS
When the user pays by card, the Workflow will decide whether a 3DS challenge is required or not. If so, Headless Universal Checkout will automatically render the 3DS challenge in context.
To improve 3DS success rates, it is recommended to pass the following elements in the Client Session:
customer.emailAddress
customer.billingAddress
Integration example snippet
Below is an example code snippet of how it all fits together.
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const container = document.getElementById('my-container') // Create containers for your hosted inputsconst cardNumberInputId = 'checkout-card-number-input'const cardNumberInputEl = document.createElement('div')cardNumberInputEl.setAttribute('id', cardNumberInputId) const cardExpiryInputId = 'checkout-card-expiry-input'const cardExpiryInputEl = document.createElement('div')cardExpiryInputEl.setAttribute('id', cardExpiryInputId) const cardCvvInputId = 'checkout-card-cvv-input'const cardCvvInputEl = document.createElement('div')cardCvvInputEl.setAttribute('id', cardCvvInputId) const cardHolderInputId = 'checkout-card-holder-input'const cardHolderInputEl = document.createElement('input')cardHolderInputEl.setAttribute('id', cardHolderInputId)cardHolderInputEl.setAttribute('placeholder', 'Cardholder Name') const submitButton = document.createElement('input')const buttonId = 'submit-button'submitButton.setAttribute('type', 'button')submitButton.setAttribute('id', buttonId)submitButton.value = 'Submit' // Add them to your containercontainer.append(cardNumberInputEl, cardExpiryInputEl, cardCvvInputEl, cardHolderInputEl, submitButton)async function configureCardForm() { const baseStyles = { height: 'auto', border: '1px solid rgb(0 0 0 / 10%)', borderRadius: '2px', padding: '12px', boxShadow: '0 4px 8px 0 rgba(0,0,0,0.2)', } // Create the payment method manager const cardManager = await headless.createPaymentMethodManager('PAYMENT_CARD') // Create the hosted inputs const { cardNumberInput, expiryInput, cvvInput } = cardManager.createHostedInputs() await Promise.all([ cardNumberInput.render(cardNumberInputId, { placeholder: '1234 1234 1234 1234', ariaLabel: 'Card number', styles: baseStyles, }), expiryInput.render(cardExpiryInputId, { placeholder: 'MM/YY', ariaLabel: 'Expiry date', styles: baseStyles, }), cvvInput.render(cardCvvInputId, { placeholder: '123', ariaLabel: 'CVV', styles: baseStyles, }), ]) // Set the cardholder name if it changes document.getElementById(cardHolderInputId).addEventListener('change', e => { cardManager.setCardholderName(e.target.value) }) // Configure event listeners for supported events cardNumberInput.addEventListener('change', (...args) => { console.log('cardNumberInput changed', ...args) }) cardNumberInput.focus() submitButton.addEventListener('click', async () => { // Validate your card input data const { valid } = await cardManager.validate() if (valid) { // Submit the card input data to Primer for tokenization await cardManager.submit() } })}
See more options and events in the SDK API Reference
Step 4.b: Handle payment methods with native buttons
This applies to PayPal, Apple Pay and Google Pay.
Some payment methods require Primer to manage the payment method’s button and implementation, and only require you to display the button to your customer.
Follow this approach when PAYPAL
, APPLE_PAY
or GOOGLE_PAY
is available as a payment method and provided via onAvailablePaymentMethodsLoad
.
Render the button
Get started by creating the payment method manager:
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const paymentMethodManager = await headless.createPaymentMethodManager('PAYPAL') // or APPLE_PAY / GOOGLE_PAY
Then, create an instance of a payment method button and render it:
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// Create the button containerconst payPalButton = document.createElement('div')const payPalButtonId = 'paypal-button'payPalButton.setAttribute('type', 'button')payPalButton.setAttribute('id', payPalButtonId) // Create and render the buttonconst button = paymentMethodManager.createButton()button.render(payPalButtonId, { buttonColor: 'silver',})
See additional style options in the SDK API Reference.
Handle button clicks (optional)
When the payment method button is clicked, Headless Universal Checkout automatically handles the rendering of the payment method screen and the payment. Based on the result of the payment, you should handle different callbacks.
- If
onCheckoutComplete
is called, show a success message and hide the button. - If
onCheckoutFail
is called, show a failure message and allow the customer to try again.
You can also listen to the click event for logging or analytics purposes:
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button.addEventListener('click', () => { // React to click // E.g. send off analytics})
Other button methods
The button object also supports other methods:
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// Hide the buttonbutton.clean() // Set the button to disabledbutton.setDisabled(true | false) // Focus the button (not supported for PayPal)button.focus() // Unfocus the button (not supported for PayPal)button.blur()
Integration example snippet
Below is an example code snippet of how it all fits together.
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// Create your button containerconst payPalButton = document.createElement('div')const payPalButtonId = 'paypal-button'payPalButton.setAttribute('type', 'button')payPalButton.setAttribute('id', payPalButtonId) function configurePayPalButton() { // Create the payment method manager const button = paymentMethodManager.createButton() // Render the button button.render(paypalButtonId, { buttonColor: 'silver', })}
Step 4.c: Handle payment methods with redirect
Some payment methods require redirecting to another web page in order to capture payment details.
Headless checkout automatically renders that web page in a popup window in order to maintain the current context.
Get started by creating a payment method manager:
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const manager = await headless.createPaymentMethodManager(paymentMethod.type)
When the user has selected the payment method, call the start
function. This function automatically:
- opens a popup to present a loading indicator, then the payment method web page
- shows an overlay on top of your page that prompts the user to focus on the popup
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myButton.addEventListener('click', () => { manager.start()})
Make sure start
is called synchronously after a click
start
opens a popup. However, most browsers have strict popup-blocking rules to protect the user. One such rule is to only allow popups that result from a direct user action.
Therefore, to ensure that the popup is properly rendered, make sure to call this function immediately after a user click.
If the browser cannot open popup windows, the current window will be redirected instead.
To ensure maximum compatibility, read the guide on how to handle redirects.