Static website generator seems to be a next big thing in web design. Now more and more web professional prefer to use because it is fast, secure and search engine friendly.
It can serve you data from variety of sources i.e. CMS (WordPress, Drupal, Joomla, Ghost etc.), Markdown, Json, Graphql etc. and generates static web pages based on provided data which can be hosted on CDN.
Gastsbyjs offer PWA (Progressive Web App) feature which means your webpages can be accessible even on slow internet or no internet connection, once loaded in web browser it caches other webpages in your browser memory which can be accessible even your web browser remain offline. PWA also enable "Add To Home Screen" function while browsing via mobile device which work like a mobile app in mobile devices.
Gatsbyjs built website can be hosted on any Serverless environment or CDN platform i.e. Cloudflare, AWS Cloudfront, Netlify, Zeit Now, AWS Amplify, Github Pages etc.
Learn more on Gatsbyjs on its website.