verdaccio/website/versioned_docs/version-5.x/uplinks.md

---
id: uplinks
title: "Uplinks"
---

An *uplink* is a link with an external registry that provides access to external packages.

![Uplinks](https://user-images.githubusercontent.com/558752/52976233-fb0e3980-33c8-11e9-8eea-5415e6018144.png)

### Usage {#usage}

```yaml
uplinks:
  npmjs:
   url: https://registry.npmjs.org/
  server2:
    url: http://mirror.local.net/
    timeout: 100ms
  server3:
    url: http://mirror2.local.net:9000/
  baduplink:
    url: http://localhost:55666/
```
### Configuration {#configuration}

You can define mutiple uplinks and each of them must have an unique name (key). They can have the following properties:

Property | Type | Required | Example | Support | Description | Default
--- | --- | --- | --- | --- | --- | ---
url | string | Yes | https://registry.npmjs.org/ | all | The registry url | npmjs
ca | string | No | ~./ssl/client.crt' | all | SSL path certificate | No default
timeout | string | No | 100ms | all | set new timeout for the request | 30s
maxage | string | No |10m | all | the time threshold to the cache is valid | 2m
fail_timeout | string | No |10m | all | defines max time when a request becomes a failure | 5m
max_fails | number | No |2 | all | limit maximun failure request | 2
cache | boolean | No |[true,false] | >= 2.1 | cache all remote tarballs in storage | true
auth | list | No | [see below](uplinks.md#auth-property)  | >= 2.5 | assigns the header 'Authorization' [more info](http://blog.npmjs.org/post/118393368555/deploying-with-npm-private-modules) | disabled
headers | list | No | authorization: "Bearer SecretJWToken==" | all | list of custom headers for the uplink | disabled
strict_ssl | boolean | No | [true,false] | >= 3.0 | If true, requires SSL certificates be valid. | true
agent_options | object | No | maxSockets: 10 | >= 4.0.2 | options for the HTTP or HTTPS Agent responsible for managing uplink connection persistence and reuse [more info](https://nodejs.org/api/http.html#http_class_http_agent) | No default

#### Auth property {#auth-property}

The `auth` property allows you to use an auth token with an uplink. Using the default environment variable:

```yaml
uplinks:
  private:
    url: https://private-registry.domain.com/registry
    auth:
      type: bearer
      token_env: true # by defaults points to the environment variable `NPM_TOKEN`
```

or via a specified _custom_ environment variable:

```yaml
uplinks:
  private:
    url: https://private-registry.domain.com/registry
    auth:
      type: bearer
      token_env: FOO_TOKEN # override the default `NPM_TOKEN` by a custom one
```

`token_env: FOO_TOKEN `internally will use `process.env['FOO_TOKEN']`

or by directly specifying a token oh the configuration file (not recommended by security corcerns):

```yaml
uplinks:
  private:
    url: https://private-registry.domain.com/registry
    auth:
      type: bearer
      token: "token"
```

> Note: `token` has priority over `token_env`

### You Must know {#you-must-know}

* Uplinks must be registries compatible with the `npm` endpoints. Eg: *verdaccio*, `sinopia@1.4.0`, *npmjs registry*, *yarn registry*, *JFrog*, *Nexus* and more.
* Setting `cache` to false will help to save space in your hard drive. This will avoid store `tarballs` but [it will keep metadata in folders](https://github.com/verdaccio/verdaccio/issues/391).
* Multiple uplinks might slow down the lookup of your packages. For each request an npm client makes, verdaccio makes 1 call to each configured uplink.
* The (timeout, maxage and fail_timeout) format follow the [NGINX measurement units](http://nginx.org/en/docs/syntax.html)
* When using the [Helm Chart](https://github.com/verdaccio/charts), you can use `secretEnvVars` to inject sensitive environment variables, which can be used to configure private uplink auth.