What are some alternatives?
When comparing Kraken and Gravity Forms, you can also consider the following products
Coinbase - Bitcoin, safe and easy.
ProntoForms - ProntoForms is a mobile business solutions application, converting paper forms onto any tablet or mobile device.
Bitfinex - Bitfinex is the largest and most advanced crypto-currencies trading platform.
Forms On Fire - Forms On Fire provides a complete, customizable mobile forms and workflow system that is reliable and secure, works offline or online.
Binance - Cryptocurrencies exchange platform
Yoast Plugins - Yoast offers plugins to improve SEO and optimize web sites and blogs.