I'm trying to figure out how to enable http2 for my rest api. I uses fastify as its server and according to their documentation secure http2 can be enabled in the following way

https://www.fastify.io/docs/latest/HTTP2

The issue I am facing now is that this api is deployed to https://www.digitalocean.com/products/app-platform on multiple server instances (for reliability and scalability)

If I understand correctly trafic is routed to these instances through cloudflare, its set up for you out of the box. I assume cloudflare also manages all ssl certificates in this case.

Thus my question, how can I specify certificate files to fastify (those .key and .cert ones) in this setup? I don't have access to cloudflare account as it is managed by Digital Ocean.