Overview

With version 2 of our Web SDK, Universal Checkout automatically creates and handles Payments by default. This greatly reduces the complexity and amount of boilerplate required to integrate Primer.

For backward compatibility reasons, it is still possible to manually create and resume payments. Follow this guide to setup Universal Checkout so that you handle the payment lifecycle.

Flow

flow

  1. 1
    Generate a clientToken on your backend by creating a Client Session with POST/client-session
  2. 2
    Initialize Universal Checkout with the clientToken to render the UI.
  3. 3
    Universal Checkout will generate a paymentMethodToken when the customer submits their payment data, or when they select particular payment methods.
  4. 4
    Create a payment using the paymentMethodToken via the Payments API POST/payments
  5. 5
    If the response indicates a requiredAction, you'll get a new clientToken.
  6. 6
    Pass the clientToken back to Universal Checkout to render next steps, like 3DS, and get a resumeToken.
  7. 7
    Call POST/payments/{id}/resume with the resumeToken to resume the payment and wrap things up. (If a new requiredAction is returned, you'll have to go back to step 5.)

Generate a Client Token

Get an API Key

You require an API Key to talk with our APIs. Head to the Developers area to manage your API keys.

When your account is created, we will also create an API token automatically. You can use this API key to get started.

Only client_tokens:write is required as the scope of the key.

Never share your API Key, only your backend should have access to it.

Find out more about API Keys in our API Reference

Generate a Client Session

Client token

A client session is the starting point for integrating payments at Primer. You can attach all the metadata associated with the order to the client session, and generate a clientToken, a temporary key used to initialize Universal Checkout.

The information you include in the client session is used in the Dashboard to conditionally route payments with Workflows, and activate payment methods and other features in Universal Checkout, so pass as much information as you can.

The X-Api-Version specifies the API version information. Earlier, this was supposed to be a date. For example, 2021-10-19.

This has changed post API version v2 which was represented by 2021-09-27 date.

Starting API version v2.1, the X-Api-Version needs to provide the API version as 2.1.

Depending upon the API version specified in the client-session request, your client-session will be processed accordingly with requisite features and options that are available for that version.

See API Reference Changelog for details.

Here is how the client session request to the Primer API should look like:

POST/client-session
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# Generate a client token with cURLcurl --location --request \  POST 'https://api.sandbox.primer.io/client-session' \  --header 'X-Api-Key: <YOUR_API_KEY>' \  --header 'X-Api-Version: 2021-10-19' \  --header 'Content-Type: application/json' \  --data '{    "orderId": "<YOUR_ORDER_ID>",    "currencyCode": "GBP",    "amount": 1200,    "customerId": "<YOUR_CUSTOMER_ID>"    "order": { "countryCode": "GB" }  }'
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To use new Workflows and all of it's exciting features, make sure to pass the following header in your API request:

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Legacy-Workflows: false
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See this migration guide for more information.

Example Response

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{  "clientToken": "<THE_CLIENT_TOKEN>",  "clientTokenExpirationDate": "2021-08-12T16:14:08.578695",  "orderId": "<YOUR_ORDER_ID>",  "currencyCode": "GBP",  "amount": 1200,  "customerId": "<YOUR_CUSTOMER_ID>",  "metadata": {},  "warnings": []}
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Make sure to pass all the information required by the payment methods and features activated on your Dashboard.

As a rule of thumb, pass as much information as you can when creating the client session. As a minimum, make sure to pass:

  • orderId
  • currencyCode
  • amount
  • order.countryCode

The clientToken is a key concept within Primer. You may receive a client token from various places but as long as you pass it to the SDK, Universal Checkout knows where to start/resume the flow.

Set up Universal Checkout

Step 1. Turn off automatic payment creation

The Universal Checkout option paymentHandling defines how the SDK should handle payment creation and resume.

Set paymentHandling to MANUAL to turn off automatic payment handling.

This disables the callbacks onBeforePayment and onCheckoutComplete.

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Primer.showUniversalCheckout(clientToken, {    /* Other options... */
    paymentHandling: 'MANUAL',})
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Step 2. Handle callbacks for creating and resuming payments

Two callbacks must be implemented:

  • onTokenizeSuccess() to create payments with paymentMethodToken
  • onResumeSuccess() to resume payments with resumeToken

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Primer.showUniversalCheckout(clientToken, {    /* Other options... */
    paymentHanding: 'MANUAL',    async onTokenizeSuccess(paymentMethodTokenData, handler) {        // Send the Payment Method Token to your server        // to create a payment using Payments API        const response = await createPayment(paymentMethodTokenData.token)
        // Call `handler.handleFailure` to cancel the flow and display an error message        if (!response) {            return handler.handleFailure('The payment failed. Please try with another payment method.')        }
        // If a new clientToken is available, call `handler.continueWithNewClientToken` to refresh the client session.        // The checkout will automatically perform the action required by the Workflow.        if (response.requiredAction.clientToken) {            return handler.continueWithNewClientToken(response.requiredAction.clientToken)        }
        // Display the success screen        return handler.handleSuccess()    },
    async onResumeSuccess(resumeTokenData, handler) {        // Send the resume token to your server to resume the payment        const response = await resumePayment(resumeTokenData.resumeToken)
        // Call `handler.handleFailure` to cancel the flow and display an error message        if (!response) {            return handler.handleFailure('The payment failed. Please try with another payment method.')        }
        // If a new clientToken is available, call `handler.continueWithNewClientToken` to refresh the client session.        // The checkout will automatically perform the action required by the Workflow        if (response.requiredAction.clientToken) {            return handler.continueWithNewClientToken(response.requiredAction.clientToken)        }
        // Display the success screen        return handler.handleSuccess()    },})
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Handle onTokenizeSuccess() callback

  • When a customer submits their payment data, the payment details are tokenized and you'll receive a paymentMethodToken in onTokenizeSuccess()
  • Create a payment request with the paymentMethodToken
  • If the payment is successful, call handler.handleSuccess() in order to display a success screen.
  • If the payment is unsuccessful, call handler.handleFailure(errorMessage) to display an error / failed message.
  • Payments API may return a new clientToken for additional steps (in the requiredActions on the response). In this case, call handler.continueWithNewClientToken(clientToken) to the checkout.

Handle onResumeSuccess() callback

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Handling onResumeSuccess() is required to fully support 3DS and the majority of payment methods.

  • You will receive a resumeToken via the onResumeSuccess() callback if applicable
  • Send a resume payment request with the resumeToken
  • If the payment is successful, call handler.handleSuccess() in order to display a success screen.
  • If the payment is unsuccessful, call handler.handleFailure(errorMessage) to display an error / failed message.
  • Payments API may again return a new clientToken for additional steps. In this case, call handler.continueWithNewClientToken(clientToken) again.