I have a surprisingly long TTFB on my website www.whisp.social and I don’t know what causes such delay. I bought my domain on NameCheap and transfered DNS to Cloudfare hoping it would reduce the TTFB.
Also I am deploying using Heroku and have professional dynos.
Could anyone please give me any advise on how to reduce the TTFB?
That will be something you have to fix on your server.
Of course you could cache your entire page, that would also “fix” the issue to the extent that most requests would be served from Cloudflare’s cache but the issue will remain. You need to find out why your server takes that long and address that.
Without knowing the server IP address it is impossible to say definitively, but in close to a 100% of the cases it is the server. Simply pause Cloudflare and check if the loading time goes down.