NextJS is the Ruby on Rails of modern development – fast, easy, and just enough framework to get a full web application up and running without getting in your way too much. The company behind the open-source project, Vercel, has successfully built a managed platform around the library that combines a CDN and edge functions to provide a fast, cheap, and scale-to-zero website that serves dynamic and static content.
Vercel is open-core – the code for Next is open-sourced, but a good chunk of functionality is hidden in proprietary Vercel code. You could theoretically deploy a Next project on your own, but it's hard to translate the build output to serverless functions and provide the middleware.
Two projects that aim to replicate the build/deploy patterns around the NextJS framework:
Serverless NextJS – provides an AWS CDK library for building and deploying Next applications to your AWS account. The GitHub readme shows a list of features they try to emulate from Vercel (that don't exist in the open-source).
OpenNext – A newer project that has the same goal. Provides a variety of deployment targets (Terraform, AWS CDK, etc.)
And another project that instead wraps Next into a new framework (tweet).
It's an interesting experiment – if these libraries deliver on their promises, customers would likely deploy in their own cloud (and, as a bonus, not pay the PaaS tax). It might show the true value of a platform like Vercel – does it come from the developer experience? The opinionated features? Managed infrastructure?