Prerequisites {#opencart-prerequisites}
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These required and optional products must be configured before using the Visa Acceptance Solutions OpenCart integration.

Required {#opencart-prerequisites_section_cg2_vz1_2kc}
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This product must be enabled and configured for your Merchant ID:

* `Unified Checkout`

{#opencart-prerequisites_ul_dg2_vz1_2kc}  
You must also have a [REST Shared Secret Key Pair](https://developer.visaacceptance.com/docs/vas/en-us/platform/developer/all/rest/rest-getting-started/restgs-jwt-shared-secret-intro/restgs-shared-secret-create-intro.md#restgs-shared-secret-create-task "") and a [Response MLE Key](https://developer.visaacceptance.com/docs/vas/en-us/platform/developer/all/rest/rest-getting-started/restgs-jwt-shared-secret-intro/restgs-mle-shared-secret-intro.md#restgs-security-mle-shared-secret-reply "").

Optional {#opencart-prerequisites_section_eg2_vz1_2kc}
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These products are optional. If you choose to use any of these products, they must be enabled and configured for your Merchant ID:

* `Decision Manager`
* `Fraud Management Essentials`
* Network Tokens

{#opencart-prerequisites_ul_fg2_vz1_2kc}  
As of version 3.0.0, accepted card brands, payment methods, Payer Authentication for `3-D Secure`, fraud screening, and payment action are configured and enabled in the `Business Center`. For more information, see the [*Unified Checkout Developer Guide*](https://developer.cybersource.com/docs/cybs/en-us/unified-checkout/developer/all/rest/unified-checkout/uc-configuration-intro/uc-enable-digital-pay-intro.md "").

Required Environment Prerequisite
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The GMP PHP extension must be enabled on your MAMP or XAMPP server for JSON Web Token messaging.