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Rhys
@rhys.dev

Small detail about the new Planetscale homepage, there's no pop in for their Sign in / Dashboard link, it's included in first HTML payload that's sent to the client A dive into how this works and why it's interesting (sub 50ms SSRing!)

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Rhys
@rhys.dev

First, a quick look at the tech stack Wappalyzer says it's Next and Remix, inspecting the HTML payload which is what we care about, it's using Remix

Rhys
@rhys.dev

Next up, the response headers what can we learn from those? They're SSRing each page load, you can tell this by how the age is 0 and the X-Vercel-Cache is MISS. Along with this, the site is hosted on Vercel meaning they're either using serverless functions or edge functions

Rhys
@rhys.dev

Loading the page from us-west it loads in 50ms-100ms Swapping my location with a VPN to Australia, the initial HTML takes 200-250ms to load This makes me think they're SSRing on the edge as if you compare those numbers to remix-on-the-edge.vercel.app/edge they're very similar

Rhys
@rhys.dev

Looking at the auth cookie, I think they're using JWTs for auth which should mean they're able to skip doing a DB lookup for the user and so the only executing cost they're paying is the trip from the client to the edge function and back