Accept card and SEPA Direct Debit payments through Adyen using PaymentKit. PaymentKit handles PCI compliance and securely orchestrates every payment operation with Adyen — 3D Secure, network tokens, off-session subscription renewals, refunds, and SEPA (euro bank debit), including its mandate and asynchronous settlement flow.

Set up summary

To accept payments with Adyen in PaymentKit, you will need to:

1. Generate Adyen API credentials
2. Confirm your Adyen account uses immediate capture
3. Connect Adyen to PaymentKit and turn on the payment methods you want
4. Configure an Adyen standard webhook and add its HMAC signing key to PaymentKit (required for refunds and SEPA)

What Adyen supports in PaymentKit

PaymentKit supports the following with Adyen:

• Card payments — one-time and customer-initiated (CIT)
• Off-session / merchant-initiated payments (MIT) — including subscription renewals and dunning retries
• 3D Secure 2 (3DS2) — both the frictionless and challenge flows
• Network tokens
• Refunds — see Refunds below
• SEPA Direct Debit — euro bank debit; see How SEPA Direct Debit works below

The following is not currently supported:

• Manual capture / authorization holds (immediate capture only — see below)
• Partial capture
• Digital wallets (Apple Pay and Google Pay)
• Adyen local payment methods
• ACH direct debit

For non-euro bank debit or any of the methods above, use a different processor.

Generate API credentials in Adyen

PaymentKit requires an API key and your merchant account name to securely connect to your Adyen account.

1. Log in to your Adyen Customer Area (use the test Customer Area for sandbox)
2. Navigate to Developers → API credentials
3. Select (or create) a web-service user, then generate an API key and copy it
4. Note your merchant account name — shown in the Customer Area account switcher

A cards-only connection needs only these values: API key, merchant account, and the environment (plus the live URL prefix in production). The webhook HMAC key described later is required for refund settlement and for SEPA.

Set your Adyen account to immediate capture

Connect Adyen to PaymentKit

1. Navigate to Orchestration → Payment processors
2. Click the add (+) button, then choose Adyen from the Payment processor list
3. Enter a Label for the connection, select the Environment (Sandbox or Production), and enter your API Key and Merchant account
4. For a Production connection, also enter your Live URL prefix
5. Turn on the payment methods you want to accept

Configure the Adyen webhook and HMAC key

Set up a standard webhook in Adyen so PaymentKit can receive asynchronous notifications.

1. In your Adyen Customer Area, navigate to Developers → Webhooks
2. Click Add webhook and choose Standard webhook
3. Under Server configuration, paste the webhook URL shown on your Adyen connection in PaymentKit. It is unique per connection and ends with your connection’s ID (a proc_… value) — for example https://<paymentkit-webhook-domain>/proc_prod_a1b2c3d4e5f6g7h8. Always copy the exact URL from the connect/edit form rather than typing it by hand
4. Enable the REFUND event so refund outcomes are delivered. If you accept SEPA, also enable the AUTHORISATION event — that is the notification that settles a SEPA charge
5. Under Security, generate an HMAC Key and copy it (Adyen issues a hex key and signs each notification with HMAC-SHA256)
6. Save the webhook, and make sure it is enabled
7. Back in PaymentKit, edit your Adyen connection and paste the key into the Webhook HMAC key field

Refunds

Adyen refunds are asynchronous. When you issue a refund, PaymentKit sends it to Adyen and records it as pending; it resolves to succeeded only once Adyen confirms it with a REFUND webhook notification.

How SEPA Direct Debit works

SEPA Direct Debit lets euro-zone customers pay directly from their bank account instead of using a card. It behaves differently from card payments, so it helps to set expectations for both you and your customers.

At checkout

1. SEPA is offered only when the payment currency is EUR and your Adyen connection has SEPA enabled with a webhook configured.
2. The customer enters their IBAN and account-holder name, and accepts a mandate — their standing authorization for you to debit the account, including future subscription renewals.
3. The payment is submitted to Adyen, which normally accepts the debit instruction and returns a processing result — not a final “paid”. (A submission Adyen cannot accept — for example a malformed IBAN — is declined immediately at checkout instead.)

Settlement is asynchronous

Money physically moves through the banking system, so the final result arrives later — typically within a few minutes in test, and anywhere from minutes to a few business days in production. Until it does:

• The payment shows as processing, not paid.
• The related invoice stays open.
• A new subscription stays incomplete — it is not activated yet, and no confirmation email is sent.

When the bank result arrives via the Adyen webhook:

• Success → the payment and its invoice are both marked paid, any subscription activates, the stored mandate is saved for future renewals, and the success receipt is sent.
• Failure (for example insufficient funds or a closed account) → the payment is marked failed and your normal dunning / decline handling runs.

SEPA refunds

SEPA refunds are asynchronous too. When you refund a settled SEPA payment, the refund is recorded as pending and resolves to succeeded — or failed if the bank rejects it — once Adyen confirms the outcome via webhook.

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