Next.js Build Performance Extremely Slow on Large Monorepo

[clarkeex]

Summary

We’re facing a critical issue with our Next.js project deployed on Vercel. Build times are extremely slow (10+ minutes) even with incremental builds enabled.

• Environment: Next.js 14, App Router, Monorepo with 12 packages
• Steps Tried:
  • Reduced dependencies
  • Split modules
  • Enabled Vercel cache

Still, deployments are slow.

Expected Behavior:
Build should complete within a few minutes.

Actual Behavior:
Build takes 10+ minutes, blocking CI/CD.

Community Question:
Should we restructure into multiple apps or optimize Next.js builds differently?

Additional information

No response

Example

No response

[clarkeex]

@selcukcukur Thanks for your detailed answer! One quick follow‑up: if we modularize the monorepo into smaller Next.js apps, how do we handle shared components and utilities without duplicating code?

[clarkeex]

@selcukcukur Thanks

[icyJoseph]

This has all the pointers or unauthentic user behavior.

The question refers to version 14 of Next.js, which is now End-of-life - no longer supported and IIRC, has a minor vulnerability for which the recommendation is to patch to 15 - not backported to 14, because once again, it is End-of-life.

The claimed steps tried by the OP are echo'ed in the answer.

• --analyze is not a command on next build
• next/dynamic is for lazy loading, and its usage is more for splitting bundles that might not be needed right away, on page load, or that would otherwise block rendering on JS parsing far too long, over an acceptable threshold
• Turbopack is stable, for dev since v15, and build since v16
• Splitting an app into multiple separate apps, is a non-starter
• Non actionable point about Vercel cache, just echoing OP's claim