What are some alternatives?
When comparing Ameto.de and Kraken, you can also consider the following products
Imagify.co - Resize, Crop and Manipulate your images on the fly!
Coinbase - Bitcoin, safe and easy.
Cloudinary - Cloudinary is a cloud-based service for hosting videos and images designed specifically with the needs of web and mobile developers in mind.
Bitfinex - Bitfinex is the largest and most advanced crypto-currencies trading platform.
Gravity Forms - Gravity Forms is one of the best and easiest contact form plugins to create modern forms for websites powered by widely-used WordPress.
LocalBitcoins.com - LocalBitcoins.com is a person-to-person bitcoin trading site.