United Kingdom

•  Worldpay is the largest payment processing company in the U.K. handling 40% of credit card transactions. However, Worldpay is not a complete ecommerce solution.
•  Shopify is the most popular ecommerce platform in the U.K. PayPal is another top payment processing company in the U.K. with 20 million U.K. users.
•  Checkout.com is the U.K.'s fastest growing fintech company that tripled its processing volume from 2017 to 2018.
• A few of the top payment processing companies for small businesses in the U.K. are Stripe, iZettle, and Square.

Netherlands

• The Netherlands B2C ecommerce market size is $17 billion as of 2015.
• The top 5 ecommerce payment processors in the Netherlands are iDeal, 2Checkout, Stripe, PayPal, and Klarna. iDeal is favored because it allows consumers to transfer money directly from bank accounts. 2Checkout out is popular since it offers 12 different payment methods (i.e., American Express, direct debit).
•  Purchases on mobile apps is one of the key factors contributing to the growth of ecommerce in the Netherlands and iDeal boosted transactions by 33.8% in 2017 because of mobile purchases.

Germany

•  Major payment processors in Germany include Adyen, Authorize.net, Klarna, PayPal, and Stripe.
• Digital wallets and ecommerce methods of payment are growing in Germany, but invoicing for buying goods online is still favored.
•  PayPal, Apple Pay, and Android Pay are expected to overtake bank transfers in Germany in a few years.
• The benefits of security and convenience, along with the usage of mobile phones, is helping to boost this type of payment.

Sweden

• While our research couldn't identify the top payment processor we were able to find some of the most popular that include: Adyen, Stripe, QuickPay, Wirecard, Braintree, and Worldpay.
• Sweden's ecommerce market is $12 billion Euro.
• Sweden is moving towards a cashless society with credit cards making up 41.5% of purchases. The country is also in the developmental stages of creating cryptocurrency.
• Klarna (a Swedish company) and PayPal seem to be the most popular payment process companies.

Austria

•  Austria has a smaller market for ecommerce than other European countries, but it is growing. Demand for local merchants and usage of mobile phones are two key factors.
• Austria has a $9.1 billion Euro ecommerce market value.
• Amazon and PayPal are two of the top companies in Austria. However, Adyen, Stripe, and Klarna are also present. Electronic Payment Standard is a popular domestic online bank that 80% of merchants in Austria accept.
• A few of the top markets for ecommerce in Austria are clothes, sporting goods, travel, and books.