Give Selected Hosts a Different Proxy in Modern Yarn

One general proxy may not suit every package source. Modern Yarn supports network settings by hostname, allowing a selected host to use a different route from the default.

For example, a project can keep one general route and select another for an internal registry:

httpsProxy: "http://203.0.113.10:8080"
networkSettings:
  "registry.example.internal":
    httpsProxy: "http://203.0.113.20:8080"

The two addresses are placeholders. For a general route to public package sources, the HTTP proxy list offers candidates when public proxies are permitted. Keep the internal registry override on its approved proxy. Put the configuration in the appropriate .yarnrc.yml for a modern Yarn release. This example selects two proxies; it does not say that the internal host should connect directly.

Match the requested hostname

The networkSettings entry applies to a hostname pattern, not a package scope or an arbitrary URL path. Keep a single-host rule exact when that is what you mean. A wildcard is useful only when you actually intend the additional hosts to share the configuration.

A package scope and a network hostname are different selectors. A scoped package can be fetched from a registry whose host is shared with other packages, while a redirected artifact can come from another hostname altogether.

Follow the complete download path

If metadata uses one host and an archive download uses another, they may match different network settings. Record the URL that actually fails before broadening the rule. “The registry worked” does not establish which route a later request selected.

Yarn's per-host settings can also include CA and other TLS configuration. Keep those decisions separate: choosing a proxy address does not by itself supply the trust required for an inspecting environment.

Make the override visible

Inspect the project's effective configuration with the tools supported by its Yarn release, then test the intended request. Avoid sharing a complete configuration dump if it includes credentials.

This feature is useful when the hosts genuinely require different routes. If every request should use the same endpoint, a single general setting is easier to maintain than a growing list of identical hostname overrides.