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Before launch

  • Production merchant account and API key are active.
  • Production website origins and return URLs are registered.
  • Production payment methods are enabled.
  • Webhook endpoint uses the production signing secret and HTTPS.
  • Signature verification and event deduplication are deployed.
  • Fulfillment waits for authoritative payment confirmation.
  • Refund, cancellation, invoice, and failed-payment paths are tested.
  • Monitoring captures request IDs, event IDs, and terminal failures without secrets.

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Switch environments

Change the API origin from https://merchant-demo.zahlo.eu to https://merchant.zahlo.eu, replace the Demo API key with the production key, and use production webhook and return URLs. Keep the change atomic so one integration does not send mixed-environment requests.

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After launch

Create a small live payment, confirm the event and fulfillment path, check the merchant dashboard, and record the deployment revision. Keep the Demo environment available for integration testing and incident reproduction.