1. PayPal: PayPal has been the leader in merchant services for years, and they remain one of the most popular choices in 2023. Their payment gateway is secure, reliable and easy to use. The company also offers fraud protection, invoicing features, customer support, and more.

2. Stripe: Stripe is another popular e-commerce merchant service provider. They offer secure payment processing, easy setup, and reliable customer support. Stripe also features fraud protection services, user analytics tools, and the ability to accept payments from all major credit cards.

3. Square: Square is a great option for smaller businesses that don’t require the full suite of features offered by larger merchant service providers. They offer simple setup, secure payment processing, and fast customer support.

4. Amazon Payments: For businesses that rely heavily on Amazon for sales, Amazon Payments is a great option. You can accept payments from customers through their mobile app or website, and you can also take advantage of their fraud protection services.

5. Braintree: Braintree is an all-in-one merchant service provider that offers everything from payment processing to fraud protection services. They also provide an extensive API for developers. This makes it easier and faster for businesses to integrate their e-commerce stores with their merchant accounts.

6. Authorize.net: Authorize.net is another reliable merchant service provider that offers a secure payment gateway, fraud protection services and invoicing features. They also provide a range of tools to help businesses manage their accounts and customers.

7. Intuit QuickBooks Payments: QuickBooks Payments is one of the leaders in merchant services for small-to-medium businesses. Their payment gateway is secure and easy to use, they offer powerful invoicing features and fraud protection services, plus they’re integrated with QuickBooks software.

8. 2Checkout: 2Checkout is another popular merchant service provider that offers a secure payment gateway, fraud protection services, user analytics tools, and more. They have an extensive library of integrations that make it easy for businesses to connect their e-commerce stores with their merchant accounts.

9. Skrill: Skrill is a comprehensive merchant service provider that offers payment processing, fraud protection services and more. They also offer online invoicing tools and the ability to accept payments from customers in over 200 countries.

10. Sage Pay: Sage Pay is a merchant service provider that specializes in providing secure payment solutions for businesses of all sizes. They offer fraud protection services, support for multiple currencies and the ability to accept payments from major credit cards.

11. Worldpay: Worldpay is another reliable merchant service provider that provides payment processing, fraud protection services and more. They offer a wide range of integrations and the ability to accept payments from customers in over 150 countries.

12. PayU: PayU is an international merchant service provider that specializes in providing secure payment solutions for businesses around the world. They offer fraud protection services, support for multiple currencies and the ability to accept payments from major credit  cards. They also have an extensive library of integrations for businesses to connect their e-commerce stores with their merchant accounts.

These  are just a few of the many e-commerce merchant service providers available. Each one offers different features, so it’s important to research each option carefully before making a decision. Consider what services you need, how much you’re willing to spend, and any other factors that will help you pick the best provider for your business.