Hey! Thanks so much for your question!
In short, yes! The JAMstack stands for JavaScript, APIs and Markup, which is an architecture for creating sites (both static and dynamic using JavAcript, API and prerenderred Markup). Basically what makes a site JAM-ey is its ability to be statically hosted on a Content Delivery Network like Netlify or Amazon’s CloudFront. The nice thing about the JAMstack (for me) is the APIs piece of it. This allows you to make a site incredibly dynamic like processing payments and doing database read/writes etc. So in a sense you get the nice bits of a full stack app without the performance latencies that often comes with it. Hurray!
There are so many ways to build a JAMstack site, so it’s hard to list them all here. But a great starting point is to start with a static site generator like Hugo, VuePress or Gatsby. It’s a great way to get started working with a JAMstack frame of mind! You can find a longer list of static site generators on staticgen.com
As for securing your applications via API keys, Netlify allows you to save your environment variables in the dashboard so you don’t have to manage that yourself. You can access that via site settings > build and deploy > environment. The really nice thing about this is that it works seamlessly with the newly released Netlify Dev workflow, which lets you replicate the netlify workflow right from your local machine. When you use Netlify Dev, and run it via netlify dev, the CLI pulls down your environment variables so you don’t even have to have a .env file on your project!
Hope that answers your questions!