---
title: 'npm Read-Through Cache'
description: 'Serve repeated npm installs from a cache close to your Nx Agents instead of the public npm registry.'
keywords:
  [npm, read-through cache, registry proxy, nx agents, nx cloud, add-on, npmrc]
sidebar:
  label: npm read-through cache
  order: 23
  badge: new!
filter: 'type:Features'
---

The npm read-through cache puts a package registry proxy close to your
[Nx Agents](/docs/features/ci-features/distribute-task-execution). The first time a package is
requested, it is fetched from the public npm registry and stored in the cache. Repeated installs of
the same package are then served from the cache instead of the upstream registry, cutting install
time and external network usage. Once the cache is warm, packages often install faster than restoring
them from `node_modules` caching.

It also protects your organization from npm registry outages.

## How to enable it

{% aside type="note" title="Requires a dedicated compute cluster" %}
The npm read-through cache is an Nx Cloud add-on that runs on a
[dedicated compute cluster](/docs/features/ci-features/dedicated-compute-cluster). Request the
cluster, then enable this add-on under **Settings > Add-ons**.
{% /aside %}

You can enable npm read-through cache through your organization settings:

1. Open **Settings > Add-ons** for your organization.
2. Under **Dedicated compute cluster** card, find **npm read-through cache** and click **Request add-on** and confirm.

When the add-on is enabled, Nx Cloud runs a caching proxy in your dedicated cluster that sits in
front of the public npm registry. You point your package manager at the proxy through an `.npmrc`
file. Installs then flow through the cache.

The cache works with **npm**, **yarn**, and **pnpm**, since they all read the `registry` setting
from `.npmrc`.

## Scope

- **Public npm packages only.** The cache proxies the public npm registry.
- **Private and scoped packages that require authentication are not cached.** Keep their existing
  registry entries in your `.npmrc`. Those requests bypass the cache and go straight to your private
  registry.

## Configuration

Point your package manager at the cache by setting the registry in an `.npmrc`. Place it in the
project root (simplest) or in the agent's home directory (`~/.npmrc`):

```ini
# .npmrc
registry=http://npm:4873/
```

The cache is always reachable from within your cluster at the address above.

{% aside type="note" title="If you publish packages" %}
If your CI publishes npm packages, set a publish registry so `npm publish` targets your real
registry instead of the cache. Add `publishConfig.registry` to the package's `package.json`, or
pass `npm publish --registry <url>`.
{% /aside %}