Set up the Lynck back office

Use this guide to connect Lynck (CrefoPay) to KORONA Event and configure the URLs that return customers to your shop and deliver payment updates. You need to save settings in both KORONA Event and the Lynck merchant portal.

Before you start

• Have administrator access to payment settings in KORONA Event and access to the correct shop in Lynck.
• Decide whether you are setting up test or live payments. Use the Lynck sandbox for test credentials and your Lynck production account for live credentials.
• Have the HTTPS address of your online shop and the account-specific API address shown in KORONA Event payment settings.
• Confirm with Lynck which payment methods are approved for your shop.

1. Connect the credentials

1. In Lynck, open Settings → Shop Information → API Credentials. Confirm that you have selected the intended shop.
2. In KORONA Event, open Admin > Payment > Lynck (CrefoPay).
3. Enter the matching credentials in Test Credentials or Live Credentials:

The private key is a secret. Copy it only into the corresponding KORONA Event credential field; do not include it in screenshots or support messages. Your merchant-portal login password is not the private key.

1. Save the KORONA Event settings. Keep Live Mode off while using sandbox credentials.

Google Pay also needs the Google Pay Console Merchant ID in KORONA Event. This is a different identifier from the Lynck Merchant ID. Wallet availability also depends on provider approval, domain setup, and the customer's device. See the payment-method reference in the payment setup overview.

2. Configure the shop URLs

In KORONA Event, find Lynck Backoffice Configuration on the Lynck payment settings page. In the Lynck portal, open Settings → Shop Configuration → URL and select Change under URL Configuration.

KORONA Event uses SecureFields in its own checkout. You do not need to configure a Lynck Hosted Page for this setup. The separate Amazon Pay field is not the generic Confirmation URL.

Return URL templates

These templates explain the values to copy. Replace YOUR-API-DOMAIN with the account-specific API hostname from your KORONA Event settings. Do not use your shop hostname or back-office hostname in its place.

Success URL:

https://YOUR-API-DOMAIN/payments/lynck/success?orderID=-ORDERID-&mac=-MAC-

Failure URL:

https://YOUR-API-DOMAIN/payments/lynck/failure?orderID=-ORDERID-&resultCode=-RESULTCODE-&merchantReference=-MERCHANTREF-&recoverable=-RECOVERABLE-&mac=-MAC-

Keep the query parameter names, capital letters, hyphens, and placeholders exactly as shown. Lynck fills them in when returning the customer. Do not replace them with an actual order number, a key, or a manually calculated value.

merchantReference identifies the payment attempt so a customer can recover safely after another failed authentication. recoverable passes Lynck's recovery indication. mac authenticates the callback. All three must remain in the failure template.

For Amazon Pay Confirmation URL, use the value copied from KORONA Event. Its structure is:

https://YOUR-SHOP-DOMAIN/de/accelerated/lynck/amazon-return?orderID=-ORDERID-&sessionID=-PAYMENTREFERENCE-&paymentMethod=-PAYMENTMETHOD-

Here YOUR-SHOP-DOMAIN is the online shop, and de is an example shop language. Preserve the language segment in the URL supplied by your KORONA Event settings.

Select Save in Lynck after entering your values.

3. Configure status notifications

Status notifications allow Lynck to send payment updates even when the customer closes the browser. The return URLs above do not replace this setup.

On Settings → Shop Configuration → URL, find System Notifications. If a notification target already exists for your KORONA Event account, open it and update that entry. Otherwise select Add. Avoid creating duplicate targets for the same account and environment.

https://YOUR-API-DOMAIN/payments/lynck/notify

Use your account's API hostname. Do not add the browser-return query parameters to this URL. Authentication uses Lynck's MAC; do not enter your Lynck login credentials in User name or Password.

Select Save. The notification target should appear as Active in the list.

4. Set up your domain for Apple Pay

If you offer Apple Pay, configure the domain where customers actually pay. Keep Lynck and KORONA Event open in separate browser tabs; you will switch between them.

Find the shop domain to enter

Open your customer-facing online shop and look at the browser's address bar. The domain is the part after https:// and before the next /. For example, if the shop address is https://tickets.example.org/de/events, enter tickets.example.org in Lynck. Keep the tickets. part, but leave out https://, /de/events, and any trailing slash. Use your own shop address, not this example.

The API address used for payment notifications, the KORONA Event back-office address, and your organization's main website may be different addresses. Use the hostname where customers open the shop and pay. If you offer checkout on several hostnames, configure each one.

Where each step happens

Provider approval alone does not complete these steps.

Standard KORONA Event shop domain

In KORONA Event, open Admin > Payment, scroll to Wallet domain setup, and find the row for your shop domain. For the standard KORONA Event shop domain, select Lynck in the Apple Pay file dropdown. For your own custom shop domain, use the upload steps below. KORONA Event serves the bundled Lynck domain association file for this selection; you do not need to download and upload that file yourself.

Selecting Lynck makes the verification file available; it does not register the domain with Lynck. Complete the registration for each domain:

1. Open https://YOUR-SHOP-DOMAIN/.well-known/apple-developer-merchantid-domain-association, replacing the placeholder with your shop hostname, and confirm that the file is reachable.
2. In the Lynck merchant area, open Settings → Apple Pay → Web, Hosted Pages & Subscriptions and check that the exact shop hostname is registered for the intended account.
3. If it is not registered, enter the hostname and select Register. Confirm successful registration before testing Apple Pay.

Your own custom shop domain

For your own shop domain, download the association file for your setup from Lynck and upload it to KORONA Event before registering the domain.

1. In the Lynck merchant area, open Settings → Apple Pay → Web, Hosted Pages & Subscriptions for the intended sandbox or live account. Enter your exact shop hostname. Prepare the verification file before selecting Register.
2. Download the domain association file provided by Lynck for this setup. Save it somewhere you can find again, such as Downloads. If the download ends in .json and the upload rejects it, follow the text-file instructions in Troubleshoot wallet payments.
3. Switch to KORONA Event. Open Admin > Payment, scroll to Wallet domain setup, and find the row for that same domain. Choose Custom upload as the Apple Pay file source, select Upload file, choose the downloaded file, and select Save file. Keep the file contents unchanged.
4. Confirm that the file is publicly reachable at https://YOUR-SHOP-DOMAIN/.well-known/apple-developer-merchantid-domain-association. Replace the domain placeholder with your own shop hostname.
5. Switch back to the Lynck tab and select Register for the same domain. Confirm successful registration before testing Apple Pay.

Uploading a file and completing Lynck's registration are separate steps. Repeat the domain setup when you change the hostname; do not copy another shop's file.

The back office groups domain verification under Admin > Payment > Wallet domain setup. For file upload details, see Troubleshoot wallet payments. If the required upload control is unavailable, contact KORONA Event support to complete the custom-domain setup.

Enable Apple Pay in KORONA Event

After domain registration succeeds, return to Admin > Payment in KORONA Event, open Lynck (CrefoPay), and select the intended Test Credentials or Live Credentials. Add Apple Pay under Activated payment methods, then select Save. Registering the domain in Lynck does not select the payment method in KORONA Event.

5. Set up Google Pay

Google Pay uses a Google merchant ID rather than the Apple Pay verification-file upload. Before starting a new Google setup, check with your First Cash or Lynck onboarding contact whether they have already arranged approval for your shop and supplied the Google merchant ID. It may be in their onboarding email. If it is missing or unclear, ask that contact for the Google Pay Console merchant ID for your shop; do not substitute the Lynck or First Cash merchant ID.

1. Obtain the ID from your approved Google Pay & Wallet Console integration or your onboarding contact.
2. In KORONA Event, open Admin > Payment > Lynck (CrefoPay) and select Live Credentials for production setup.
3. Paste the Google ID into Google Pay Console Merchant ID, below Lynck Merchant ID. Keep your Lynck ID in its own field.
4. Add Google Pay under Activated payment methods and select Save. Google Pay is available for selection only after its merchant-ID field contains a value.
5. Confirm with Lynck that Google Pay Express is enabled for the same live merchant and store and uses this Google ID.

If approval has not been arranged, follow Prepare Lynck Google Pay for production before enabling live payments. Test credentials and live credentials have separate settings; a working sandbox button does not establish live approval.

6. Prepare payments for launch

In Lynck, check the approved methods under Settings > Payment Method Configuration. Then enable the intended online payment methods in KORONA Event. Keep automatic capture aligned with your agreed payment process; do not change capture behavior just to complete URL setup.

Use your test shop and Lynck sandbox before switching to live payments. Complete a successful test payment and a canceled authentication followed by a retry. Follow Review the customer checkout before launch for the wider checkout preparation.

For launch, select the corresponding production shop in Lynck, configure its URLs and notification target, and save the matching Live Credentials in KORONA Event. Enable Live Mode only when the live setup and provider approval are complete. Saving sandbox settings does not configure your production shop.

If setup does not work

If the configuration is complete but payments still do not work, contact KORONA Event support. Do not repeatedly submit a payment whose outcome is still pending.

Related articles

• Payment setup overview
• Review the customer checkout before launch
• Send or copy a payment link