TL;DR

A Cloudflare engineering director spent roughly £800 on Anthropic Claude tokens to reimplement 94% of the Next.js API in a week, creating an open-source alternative called Vinext that uses Vite instead of Turbopack and delivers up to 4.4x faster builds.

Breaking free from Vercel lock-in

Steve Faulkner, Cloudflare’s engineering director, built Vinext to tackle a longstanding frustration: deploying Next.js with full features on platforms other than Vercel requires reshaping bespoke build output for each target. While Vercel has announced “deployment adapters” to address this, Faulkner considers them an “early effort” that still depends on the proprietary Turbopack bundler.

Existing workarounds through the OpenNext project, sponsored by SST, Cloudflare, and Netlify, proved to be a “difficult and fragile process” that broke unpredictably between Next.js versions.

How it was built

Faulkner spent two hours defining the architecture with Claude in OpenCode, an open-source AI coding agent, then directed the AI to implement the API piece by piece using the existing Next.js test suite to catch issues. The project leveraged Vite’s plugin for React Server Components and the wealth of Next.js documentation available for AI systems to reference.

“Although AI wrote the code, the human element was critical,” Faulkner said, noting he “had to course-correct regularly.” The README carries a clear warning: no human has reviewed the code, and the project remains under heavy development.

Early results and implications

Benchmarks show build times up to 4.4x faster than Next.js 16 with Turbopack, and client bundle sizes roughly 56% smaller. The only deployment target currently supported is Cloudflare Workers, though a proof of concept already runs on Vercel.

The project raises broader questions about using AI to reimplement widely used APIs as a strategy against vendor lock-in, and about the feasibility of software projects where no human fully understands the codebase.

Looking forward

If Vinext matures, it could offer Next.js developers a genuine alternative to Vercel’s toolchain. But the project also underscores a tension in AI-generated code: the speed gains are real, but so is the risk of maintaining software that no human has comprehensively reviewed.