Currently none of the HTTP2-specific APIs are available through Fastify, but Node's req and can be access through our Request and interface. PRs are welcome.

ALPN negotiation allows to support both HTTPS and HTTP/2 over the same socket. Node core req and objects can be either or HTTP/2. Fastify supports this out of the box:

Plain or insecure

If you are building microservices, you can connect to HTTP2 in plain text, however this is not supported by browsers.