Mollie

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Execute the approved action

const payment = await (await fetch('https://api.mollie.com/v2/payments', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.MOLLIE_API_KEY}`,   // test_ or live_ key, server-side only
    'Content-Type': 'application/json',
    'Idempotency-Key': 'booking-2026-08-04-001',             // your external_action_reference
  },
  body: JSON.stringify({
    amount: { currency: 'EUR', value: '189.00' },            // decimal string: EUR 189.00
    description: 'Attesso booking 2026-08-04-001',
    redirectUrl: 'https://your-app.example/mollie/return',
    webhookUrl: 'https://your-app.example/mollie/webhook',   // must be publicly reachable; Mollie validates at creation
    metadata: { attesso_mandate_id: 'mnd_...', attesso_authorization_id: 'aut_...', external_action_reference: 'booking-2026-08-04-001' },
  }),
})).json();

// payment.id (tr_...) is your provider_transaction_reference; redirect the
// payer to payment._links.checkout.href when a checkout is needed.

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Report the outcome to Attesso

• Definite acceptance (paid, or authorized for manually captured methods): commit with provider_transaction_reference: payment.id.
• Definite non-acceptance (failed, expired, canceled): cancel with reason: EXECUTION_FAILED (use EXECUTOR_REJECTED when Mollie refuses the action outright). With an earlier ALLOW, the disposition is NO_LONGER_POSSIBLE.
• A refund after commit is not an authorization transition; report it so the signed evidence carries the claim (Refund reports).
• open, pending (or a still-open checkout): not final; do not commit or cancel yet.
• A timeout or lost response: reconcile before deciding (below).

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Webhooks

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Reconcile a lost response

• Retry the identical create call with the same Idempotency-Key: Mollie returns the original response (Idempotent-Replayed: true header); a 409 Conflict means the first request is still in flight; a reused key with different bytes is a 400.
• Keys survive for one hour; after that the same key is a new request.
• Find the payment by listing payments and matching your metadata values, or retrieve it directly by its tr_ id.

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Test mode

• Selecting paid in the test checkout completes the payment and returns the payer to redirectUrl.
• To exercise a failed payment, pin "method": "creditcard" at creation and use a documented magic amount from Mollie’s testing reference, for example 1007.00 -> insufficient_funds, then select Failed on the status screen. A payment created without a pinned method bounces non-paid selections back to method selection and stays open; open test payments are not cancelable via the API (DELETE /payments/{id} -> 422).
• On paid test payments, Mollie adds a changePaymentState link for testing refunds and chargebacks.

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Rehearsal

curl -O https://raw.githubusercontent.com/douwe-kramer/docs/main/examples/mollie-e2e.mjs
MOLLIE_API_KEY=test_... node mollie-e2e.mjs