Amazon S3 or Amazon Simple Storage Service is a service offered by Amazon Web Services (AWS) that provides object storage through a web service interface.
Fastly is a cloud computing services provider. Fastly's cloud platform provides a content delivery network, Internet security services, load balancing, and video & streaming services.
GitHub Pages is a static site hosting service.
Mailchimp is a marketing automation platform and email marketing service.
MkDocs is a static site generator, used for building project documentation.
Varnish is a reverse caching proxy.