How Vercel builds Vercel

Was watching this @leeerob video on How Vercel builds Vercel and had some thoughts.

(shameless plug: I did a How Prezly uses Prezly to run Prezly post a few years back)

Monitoring App

Around minute 8 Rob demonstrates a monitoring tab that we don't have in our vercel account. I'm curious on how to access that feature but also how it's built. It looks a lot like the charts we're seeing in Grafana which is the tool we're using to monitor logs.

Using Contentful

Surprised to learn they are using Contentful and are seeing similar build times of 9+ minutes and a nice way to preview content before they hit 'publish'

I'd love to understand their motivation around using Contentful vs a self-hosted option but what I am particularry interested is the way they preview content. From the screen share I think I can see that they are not using Contentful Live preview but are leveraging their menu-bar which knows that a user is logged in and can therefore load the content from the contentful preview API in addition to having static generation on site build. Nice!

Personally I am considering replacing Contentful with PayloadCMS but still experimenting with it.

Feature Flags

To test features before they go live or to gradually roll out new functionality Vercel is using the concept of feature flags powered by LaunchDarkly. At Prezly we have our own self-built solution which is nothing more than a JSON data column that is available on user and company entities.

Now if I want to test a feature flag in production I have to open our admin tools and enable it for that user or account to then refresh the page (and refetch user context).

I like the menu-bar that allows admins to enable or disable features on the fly which is a great, and easy to build, add-on that can save us all quite some time.


My overall feeling of watching the video is that we're doing quite well. It was great to hear that even companies like Vercel have tech debt (still on app + pages router). ​

Additionally i discovered that most things Rob talks about in the video are concepts we have applied at Prezly oftentimes without using Vercel components though.

Anything you learned from Rob's video?