JavaScript, API & Markup. Per CEO & Co-founder of Netlify Mathias Biilmann:
"[JAMstack is] a modern web development architecture based on client-side JavaScript, reusable APIs, and prebuilt Markup."
Dynamic functionality is handled by JavaScript. There are no restrictions to which framework or libraries are available. In the case of this site, I've opted for Gridsome.
Server side operations are abstracted into reusable APIs and accessed over HTTPS with JavaScript. These can be third party services (like the FormSpree form on the contact section of this site!) or custom functions you deploy to Netlify Functions, AWS Lambda, or Microsoft Azure Functions. These services afford us API endpoints which invoke a JavaScript functions when called. This "serverless" architecture allows us to scale quickly without maintaining a back-end codebase!
Every page on this site is served as a static HTML file. These are generated from source files, in this case Markdown. Gridsome eats up my Markdown via GraphQL (this could easily be calling a content API like SiteLeaf) and pipes the data into our own templates. These statically generated pages can be combined with the power of Vue to bring the best parts of Single Page Applications and Server Side Rendering together at last.
Please, reach out!