[BUG]: Cannot find module 'varlock', on Vercel

[violabg]

varlock version

0.7.2

Steps to reproduce

My app is using varlock with pass, I have deployed on vercel and it was working fine, but now after some code updates not related to varlock is giving me and error.
Locally testing with the build is working fine.

next.config.ts

import { varlockNextConfigPlugin } from "@varlock/nextjs-integration/plugin";
import type { NextConfig } from "next";

const nextConfig: NextConfig = {
  experimental: {
    viewTransition: true,
  },
  images: {
    dangerouslyAllowSVG: true,
    contentDispositionType: "attachment",
    contentSecurityPolicy: "default-src 'self'; script-src 'none'; sandbox;",
  },
}

export default varlockNextConfigPlugin()(nextConfig);

package.json

{
  "name": "ai-talks",
  "version": "1.0.0",
  "private": true,
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start",
    "lint": "eslint"
  },
  "dependencies": {
    "@base-ui/react": "^1.3.0",
    "@tailwindcss/typography": "^0.5.19",
    "@upstash/redis": "^1.37.0",
    "@varlock/nextjs-integration": "^0.3.3",
    "@varlock/pass-plugin": "^0.0.6",
    "better-auth": "^1.6.2",
    "class-variance-authority": "^0.7.1",
    "clsx": "^2.1.1",
    "geist": "^1.7.0",
    "github-slugger": "^2.0.0",
    "gray-matter": "^4.0.3",
    "lucide-react": "^1.8.0",
    "motion": "^12.38.0",
    "next": "16.2.3",
    "next-mdx-remote": "^6.0.0",
    "next-themes": "^0.4.6",
    "react": "19.2.5",
    "react-dom": "19.2.5",
    "rehype-autolink-headings": "^7.1.0",
    "rehype-pretty-code": "^0.14.3",
    "rehype-slug": "^6.0.0",
    "remark-gfm": "^4.0.1",
    "shadcn": "^4.2.0",
    "tailwind-merge": "^3.5.0",
    "tw-animate-css": "^1.4.0",
    "varlock": "^0.7.2"
  },
  "devDependencies": {
    "@tailwindcss/postcss": "^4.2.2",
    "@types/github-slugger": "^2.0.0",
    "@types/mdx": "^2.0.13",
    "@types/node": "^25.6.0",
    "@types/react": "^19.2.14",
    "@types/react-dom": "^19.2.3",
    "eslint": "^9.39.4",
    "eslint-config-next": "16.2.3",
    "tailwindcss": "^4.2.2",
    "typescript": "^6.0.2"
  },
  "overrides": {
    "next": {
      "@next/env": "npm:@varlock/nextjs-integration"
    },
    "other-dep": {
      "dotenv": "npm:varlock"
    }
  }
}

What is expected?

to work on Vercel

What is actually happening?

error on Vercel log when trying to access the site

2026-04-10 15:37:36.638 [error] Cannot find module 'varlock'
Require stack:

• /var/task/node_modules/@next/env/dist/next-env-compat.js
• /var/task/___next_launcher.cjs
  Did you forget to add it to "dependencies" in package.json?
  Node.js process exited with exit status: 1. The logs above can help with debugging the issue.

System Info

Any additional comments?

I'm not sure if is a vercel problem since I have deployed an older version that was working and now is giving the same error

[theoephraim]

I’ll dig in a bit. A minimal repro would be very helpful!

[theoephraim]

not totally sure, but maybe this could have something to do with it - vercel/next.js#91663
try pinning next @ 16.1.7

[violabg]

not totally sure, but maybe this could have something to do with it - vercel/next.js#91663 try pinning next @ 16.1.7

yes it's that, using next 16.1.7 works

but it's weird because I'm pretty sure I had some build working with the latest 16.2...