# Direct API Integration

Businesses not using an e-commerce service can integrate the April API directly into their existing services.

For businesses upgrading from Limepay API, please refer to our [Migration guide](/developer-portal/migration-guide).

1. **Choosing how to pay**


For most custom integrations, if your customers are using cards to make payments, the best way to capture
these card details in a PCI-compliant manner is to use the April checkout. For details on this, see [Checkout integration](/developer-portal/checkout-integration).

We also provide an API solution that includes a few alternatives for how to set up a payment.
See [Payment capture API](/developer-portal/payment-capture-api)

1. **[Processing the payment](/developer-portal/payments)**


Wire up the necessary API to ensure customer payments can be received and processed.

1. **[Error and payment action handling](/developer-portal/error-handling)**


Configure the integration to handle inevitable complications from human error or card security checks,
including 3D-Secure security challenges.

1. **[Testing the integration](/developer-portal/testing)**


Test the functionality of the integration.

## Further integration options

Once the standard integration has been completed, merchants may wish to consider these features:

- **[3D-Secure](/developer-portal/three-d-secure)** - enable an extra level of security on transactions.
- **[Know Your Customer (KYC)](/developer-portal/know-your-customer-b2c)** - merchants can pre-register customers for KYC checks before they use the checkout.
- **[Payment authorisation (pre-auth)](/developer-portal/payment-authorisation)** - Reserve funds on a customer's card before processing the order.
- **[Capturing payment sources](/developer-portal/payment-sources)** - Capture payment sources to process payments directly.
- **[Payment surcharging](/developer-portal/payment-surcharging)** - Pass on merchant platform fees to the customer.


br
br
**[Return to documentation home](/)**