---
title: npm-cache
section: 1
description: Manipulates packages cache
---

### Synopsis

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### Description

Used to add, list, or clean the npm cache folder.

* add:
  Add the specified packages to the local cache.  This command is primarily
  intended to be used internally by npm, but it can provide a way to
  add data to the local installation cache explicitly.

* clean:
  Delete all data out of the cache folder.  Note that this is typically
  unnecessary, as npm's cache is self-healing and resistant to data
  corruption issues.

* verify:
  Verify the contents of the cache folder, garbage collecting any unneeded
  data, and verifying the integrity of the cache index and all cached data.

### Details

npm stores cache data in an opaque directory within the configured `cache`,
named `_cacache`. This directory is a
[`cacache`](http://npm.im/cacache)-based content-addressable cache that
stores all http request data as well as other package-related data. This
directory is primarily accessed through `pacote`, the library responsible
for all package fetching as of npm@5.

All data that passes through the cache is fully verified for integrity on
both insertion and extraction. Cache corruption will either trigger an
error, or signal to `pacote` that the data must be refetched, which it will
do automatically. For this reason, it should never be necessary to clear
the cache for any reason other than reclaiming disk space, thus why `clean`
now requires `--force` to run.

There is currently no method exposed through npm to inspect or directly
manage the contents of this cache. In order to access it, `cacache` must be
used directly.

npm will not remove data by itself: the cache will grow as new packages are
installed.

### A note about the cache's design

The npm cache is strictly a cache: it should not be relied upon as a
persistent and reliable data store for package data. npm makes no guarantee
that a previously-cached piece of data will be available later, and will
automatically delete corrupted contents. The primary guarantee that the
cache makes is that, if it does return data, that data will be exactly the
data that was inserted.

To run an offline verification of existing cache contents, use `npm cache
verify`.

### Configuration

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### See Also

* [package spec](/using-npm/package-spec)
* [npm folders](/configuring-npm/folders)
* [npm config](/commands/npm-config)
* [npmrc](/configuring-npm/npmrc)
* [npm install](/commands/npm-install)
* [npm publish](/commands/npm-publish)
* [npm pack](/commands/npm-pack)
* https://npm.im/cacache
* https://npm.im/pacote
* https://npm.im/@npmcli/arborist
* https://npm.im/make-fetch-happen
