---
source: https://iinventedlight.com/library/notes/nextjs-optimize-package-imports.md
title: "optimizePackageImports for large barrel files"
license: CC-BY-4.0
license_url: https://creativecommons.org/licenses/by/4.0/
source_license: "MIT (vercel/next.js); prose restates cited source lines in own words"
license_family: nextjs-mit
attribution: "Summary by iinventedlight (AI-assisted). Sources: Next.js docs, optimizePackageImports, MIT (vercel/next.js); Next.js docs, Package bundling, MIT (vercel/next.js). Copyright (c) 2025 Vercel, Inc. MIT (https://raw.githubusercontent.com/vercel/next.js/canary/license.md)."
author: "iinventedlight (synthesis of cited sources); text drafted with AI assistance"
date: 2026-11-09
status: published
approved_by: "Cole Withington, 2026-11-09 13:04 PT: \"Yes, publish all 33 Next.js drafts\""
checked_on: 2026-11-09
as_of: 2026-11-09
confidence: medium
untested: "No Next.js app was run for this note; only the fetched documentation pages were read."
category: coding-references
topic_area: "code-web: Next.js bundling"
tags: [nextjs, bundling]
client: Librarian
sources:
  - id: S1
    title: "optimizePackageImports"
    publisher: Next.js docs
    url: https://nextjs.org/docs/app/api-reference/config/next-config-js/optimizePackageImports
    accessed: 2026-11-09
    license: "MIT (vercel/next.js)"
  - id: S2
    title: "Package bundling"
    publisher: Next.js docs
    url: https://nextjs.org/docs/app/guides/package-bundling
    accessed: 2026-11-09
    license: "MIT (vercel/next.js)"
---
# optimizePackageImports for large barrel files

**Answer:** Some packages can export hundreds or thousands of modules, which can cause performance issues. Adding a package to `optimizePackageImports` will only load the modules you are actually using.

## Bundling

Bundling combines your application code with its dependencies into optimized output files. Next.js automatically optimizes bundles by code splitting, tree-shaking, and other techniques.

## See also

- [nextjs-lazy-loading](https://iinventedlight.com/library/notes/nextjs-lazy-loading/)
- [nextjs-scripts](https://iinventedlight.com/library/notes/nextjs-scripts/)

## Claims

- id: C1
  claim: Large barrel packages hurt performance.
  source: S1
  evidence: "Some packages can export hundreds or thousands of modules, which"

- id: C2
  claim: optimizePackageImports loads only used modules.
  source: S1
  evidence: "Adding a package to `experimental.optimizePackageImports` will only load the modules you are actually using,"

- id: C3
  claim: Bundling combines code into optimized outputs.
  source: S2
  evidence: "Bundling is the process of combining your application code and"

- id: C4
  claim: Next.js auto-optimizes with code splitting.
  source: S2
  evidence: "Next.js automatically optimizes bundles by code splitting, tree-shaking, and other techniques."

## Sources

- [S1] optimizePackageImports. Next.js docs. https://nextjs.org/docs/app/api-reference/config/next-config-js/optimizePackageImports . License: MIT (vercel/next.js). Accessed 2026-11-09.

- [S2] Package bundling. Next.js docs. https://nextjs.org/docs/app/guides/package-bundling . License: MIT (vercel/next.js). Accessed 2026-11-09.


License: this note is CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Summary by iinventedlight (AI-assisted). Copyright (c) 2025 Vercel, Inc. Sources: Next.js docs (vercel/next.js on GitHub / nextjs.org), MIT (https://raw.githubusercontent.com/vercel/next.js/canary/license.md). Text was condensed and changed from the originals.

---

Agents: [/agents.md](/agents.md) | [/.well-known/agent-library.json](/.well-known/agent-library.json).