diff --git a/cli/args/mod.rs b/cli/args/mod.rs
index d8f5531015..927f43e85a 100644
--- a/cli/args/mod.rs
+++ b/cli/args/mod.rs
@@ -578,6 +578,7 @@ fn discover_npmrc(
     let resolved = npmrc
       .as_resolved(npm_registry_url())
       .context("Failed to resolve .npmrc options")?;
+    log::debug!(".npmrc found at: '{}'", path.display());
     Ok(Arc::new(resolved))
   }
 
diff --git a/cli/cache/mod.rs b/cli/cache/mod.rs
index ded163b4e4..bf8f1b1f0b 100644
--- a/cli/cache/mod.rs
+++ b/cli/cache/mod.rs
@@ -378,6 +378,7 @@ impl Loader for FetchCacher {
             } else {
               FetchPermissionsOptionRef::DynamicContainer(&permissions)
             },
+            maybe_auth: None,
             maybe_accept: None,
             maybe_cache_setting: maybe_cache_setting.as_ref(),
           },
diff --git a/cli/file_fetcher.rs b/cli/file_fetcher.rs
index e92aca5420..95d778f0bb 100644
--- a/cli/file_fetcher.rs
+++ b/cli/file_fetcher.rs
@@ -24,6 +24,7 @@ use deno_graph::source::LoaderChecksum;
 use deno_path_util::url_to_file_path;
 use deno_runtime::deno_permissions::PermissionsContainer;
 use deno_runtime::deno_web::BlobStore;
+use http::header;
 use log::debug;
 use std::borrow::Cow;
 use std::collections::HashMap;
@@ -181,6 +182,7 @@ pub enum FetchPermissionsOptionRef<'a> {
 pub struct FetchOptions<'a> {
   pub specifier: &'a ModuleSpecifier,
   pub permissions: FetchPermissionsOptionRef<'a>,
+  pub maybe_auth: Option<(header::HeaderName, header::HeaderValue)>,
   pub maybe_accept: Option<&'a str>,
   pub maybe_cache_setting: Option<&'a CacheSetting>,
 }
@@ -350,6 +352,7 @@ impl FileFetcher {
     maybe_accept: Option<&str>,
     cache_setting: &CacheSetting,
     maybe_checksum: Option<&LoaderChecksum>,
+    maybe_auth: Option<(header::HeaderName, header::HeaderValue)>,
   ) -> Result<FileOrRedirect, AnyError> {
     debug!(
       "FileFetcher::fetch_remote_no_follow - specifier: {}",
@@ -442,6 +445,7 @@ impl FileFetcher {
             .as_ref()
             .map(|(_, etag)| etag.clone()),
           maybe_auth_token: maybe_auth_token.clone(),
+          maybe_auth: maybe_auth.clone(),
           maybe_progress_guard: maybe_progress_guard.as_ref(),
         })
         .await?
@@ -538,7 +542,18 @@ impl FileFetcher {
     specifier: &ModuleSpecifier,
   ) -> Result<File, AnyError> {
     self
-      .fetch_inner(specifier, FetchPermissionsOptionRef::AllowAll)
+      .fetch_inner(specifier, None, FetchPermissionsOptionRef::AllowAll)
+      .await
+  }
+
+  #[inline(always)]
+  pub async fn fetch_bypass_permissions_with_maybe_auth(
+    &self,
+    specifier: &ModuleSpecifier,
+    maybe_auth: Option<(header::HeaderName, header::HeaderValue)>,
+  ) -> Result<File, AnyError> {
+    self
+      .fetch_inner(specifier, maybe_auth, FetchPermissionsOptionRef::AllowAll)
       .await
   }
 
@@ -552,6 +567,7 @@ impl FileFetcher {
     self
       .fetch_inner(
         specifier,
+        None,
         FetchPermissionsOptionRef::StaticContainer(permissions),
       )
       .await
@@ -560,12 +576,14 @@ impl FileFetcher {
   async fn fetch_inner(
     &self,
     specifier: &ModuleSpecifier,
+    maybe_auth: Option<(header::HeaderName, header::HeaderValue)>,
     permissions: FetchPermissionsOptionRef<'_>,
   ) -> Result<File, AnyError> {
     self
       .fetch_with_options(FetchOptions {
         specifier,
         permissions,
+        maybe_auth,
         maybe_accept: None,
         maybe_cache_setting: None,
       })
@@ -585,12 +603,14 @@ impl FileFetcher {
     max_redirect: usize,
   ) -> Result<File, AnyError> {
     let mut specifier = Cow::Borrowed(options.specifier);
+    let mut maybe_auth = options.maybe_auth.clone();
     for _ in 0..=max_redirect {
       match self
         .fetch_no_follow_with_options(FetchNoFollowOptions {
           fetch_options: FetchOptions {
             specifier: &specifier,
             permissions: options.permissions,
+            maybe_auth: maybe_auth.clone(),
             maybe_accept: options.maybe_accept,
             maybe_cache_setting: options.maybe_cache_setting,
           },
@@ -602,6 +622,10 @@ impl FileFetcher {
           return Ok(file);
         }
         FileOrRedirect::Redirect(redirect_specifier) => {
+          // If we were redirected to another origin, don't send the auth header anymore.
+          if redirect_specifier.origin() != specifier.origin() {
+            maybe_auth = None;
+          }
           specifier = Cow::Owned(redirect_specifier);
         }
       }
@@ -666,6 +690,7 @@ impl FileFetcher {
           options.maybe_accept,
           options.maybe_cache_setting.unwrap_or(&self.cache_setting),
           maybe_checksum,
+          options.maybe_auth,
         )
         .await
     }
@@ -756,6 +781,7 @@ mod tests {
         FetchOptions {
           specifier,
           permissions: FetchPermissionsOptionRef::AllowAll,
+          maybe_auth: None,
           maybe_accept: None,
           maybe_cache_setting: Some(&file_fetcher.cache_setting),
         },
@@ -1255,6 +1281,7 @@ mod tests {
         FetchOptions {
           specifier: &specifier,
           permissions: FetchPermissionsOptionRef::AllowAll,
+          maybe_auth: None,
           maybe_accept: None,
           maybe_cache_setting: Some(&file_fetcher.cache_setting),
         },
@@ -1268,6 +1295,7 @@ mod tests {
         FetchOptions {
           specifier: &specifier,
           permissions: FetchPermissionsOptionRef::AllowAll,
+          maybe_auth: None,
           maybe_accept: None,
           maybe_cache_setting: Some(&file_fetcher.cache_setting),
         },
diff --git a/cli/http_util.rs b/cli/http_util.rs
index 9c9ae9e413..4b17936d68 100644
--- a/cli/http_util.rs
+++ b/cli/http_util.rs
@@ -19,6 +19,7 @@ use deno_runtime::deno_fetch;
 use deno_runtime::deno_fetch::create_http_client;
 use deno_runtime::deno_fetch::CreateHttpClientOptions;
 use deno_runtime::deno_tls::RootCertStoreProvider;
+use http::header;
 use http::header::HeaderName;
 use http::header::HeaderValue;
 use http::header::ACCEPT;
@@ -204,6 +205,7 @@ pub struct FetchOnceArgs<'a> {
   pub maybe_accept: Option<String>,
   pub maybe_etag: Option<String>,
   pub maybe_auth_token: Option<AuthToken>,
+  pub maybe_auth: Option<(header::HeaderName, header::HeaderValue)>,
   pub maybe_progress_guard: Option<&'a UpdateGuard>,
 }
 
@@ -382,6 +384,8 @@ impl HttpClient {
       request
         .headers_mut()
         .insert(AUTHORIZATION, authorization_val);
+    } else if let Some((header, value)) = args.maybe_auth {
+      request.headers_mut().insert(header, value);
     }
     if let Some(accept) = args.maybe_accept {
       let accepts_val = HeaderValue::from_str(&accept)?;
@@ -792,6 +796,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -818,6 +823,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -845,6 +851,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -866,6 +873,7 @@ mod test {
         maybe_etag: Some("33a64df551425fcc55e".to_string()),
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     assert_eq!(res.unwrap(), FetchOnceResult::NotModified);
@@ -885,6 +893,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -914,6 +923,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, _)) = result {
@@ -939,6 +949,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Redirect(url, _)) = result {
@@ -974,6 +985,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -1021,6 +1033,7 @@ mod test {
           maybe_etag: None,
           maybe_auth_token: None,
           maybe_progress_guard: None,
+          maybe_auth: None,
         })
         .await;
 
@@ -1083,6 +1096,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
 
@@ -1136,6 +1150,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -1177,6 +1192,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -1199,6 +1215,7 @@ mod test {
         maybe_etag: Some("33a64df551425fcc55e".to_string()),
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     assert_eq!(res.unwrap(), FetchOnceResult::NotModified);
@@ -1233,6 +1250,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     if let Ok(FetchOnceResult::Code(body, headers)) = result {
@@ -1262,6 +1280,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
     assert!(result.is_err());
@@ -1283,6 +1302,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
 
@@ -1306,6 +1326,7 @@ mod test {
         maybe_etag: None,
         maybe_auth_token: None,
         maybe_progress_guard: None,
+        maybe_auth: None,
       })
       .await;
 
diff --git a/cli/lsp/npm.rs b/cli/lsp/npm.rs
index 8bdeb7e7d8..2decfc3429 100644
--- a/cli/lsp/npm.rs
+++ b/cli/lsp/npm.rs
@@ -4,6 +4,7 @@ use dashmap::DashMap;
 use deno_core::anyhow::anyhow;
 use deno_core::error::AnyError;
 use deno_core::serde_json;
+use deno_npm::npm_rc::NpmRc;
 use deno_semver::package::PackageNv;
 use deno_semver::Version;
 use serde::Deserialize;
@@ -25,7 +26,10 @@ pub struct CliNpmSearchApi {
 
 impl CliNpmSearchApi {
   pub fn new(file_fetcher: Arc<FileFetcher>) -> Self {
-    let resolver = NpmFetchResolver::new(file_fetcher.clone());
+    let resolver = NpmFetchResolver::new(
+      file_fetcher.clone(),
+      Arc::new(NpmRc::default().as_resolved(npm_registry_url()).unwrap()),
+    );
     Self {
       file_fetcher,
       resolver,
diff --git a/cli/lsp/registries.rs b/cli/lsp/registries.rs
index 5f7ce00823..ade353e683 100644
--- a/cli/lsp/registries.rs
+++ b/cli/lsp/registries.rs
@@ -482,6 +482,7 @@ impl ModuleRegistry {
         .fetch_with_options(FetchOptions {
           specifier: &specifier,
           permissions: FetchPermissionsOptionRef::AllowAll,
+          maybe_auth: None,
           maybe_accept: Some("application/vnd.deno.reg.v2+json, application/vnd.deno.reg.v1+json;q=0.9, application/json;q=0.8"),
           maybe_cache_setting: None,
         })
diff --git a/cli/npm/managed/cache/mod.rs b/cli/npm/managed/cache/mod.rs
index fa0e8c8a59..aaec486681 100644
--- a/cli/npm/managed/cache/mod.rs
+++ b/cli/npm/managed/cache/mod.rs
@@ -26,7 +26,7 @@ use crate::cache::CACHE_PERM;
 use crate::util::fs::atomic_write_file_with_retries;
 use crate::util::fs::hard_link_dir_recursive;
 
-mod registry_info;
+pub mod registry_info;
 mod tarball;
 mod tarball_extract;
 
diff --git a/cli/npm/managed/cache/registry_info.rs b/cli/npm/managed/cache/registry_info.rs
index 6c4a7503b5..6d39d3c13f 100644
--- a/cli/npm/managed/cache/registry_info.rs
+++ b/cli/npm/managed/cache/registry_info.rs
@@ -84,7 +84,7 @@ impl RegistryInfoDownloader {
     self.load_package_info_inner(name).await.with_context(|| {
       format!(
         "Error getting response at {} for package \"{}\"",
-        self.get_package_url(name),
+        get_package_url(&self.npmrc, name),
         name
       )
     })
@@ -190,7 +190,7 @@ impl RegistryInfoDownloader {
 
   fn create_load_future(self: &Arc<Self>, name: &str) -> LoadFuture {
     let downloader = self.clone();
-    let package_url = self.get_package_url(name);
+    let package_url = get_package_url(&self.npmrc, name);
     let registry_config = self.npmrc.get_registry_config(name);
     let maybe_auth_header =
       match maybe_auth_header_for_npm_registry(registry_config) {
@@ -239,36 +239,36 @@ impl RegistryInfoDownloader {
     .map(|r| r.map_err(Arc::new))
     .boxed_local()
   }
-
-  fn get_package_url(&self, name: &str) -> Url {
-    let registry_url = self.npmrc.get_registry_url(name);
-    // The '/' character in scoped package names "@scope/name" must be
-    // encoded for older third party registries. Newer registries and
-    // npm itself support both ways
-    //   - encoded: https://registry.npmjs.org/@rollup%2fplugin-json
-    //   - non-ecoded: https://registry.npmjs.org/@rollup/plugin-json
-    // To support as many third party registries as possible we'll
-    // always encode the '/' character.
-
-    // list of all characters used in npm packages:
-    //  !, ', (, ), *, -, ., /, [0-9], @, [A-Za-z], _, ~
-    const ASCII_SET: percent_encoding::AsciiSet =
-      percent_encoding::NON_ALPHANUMERIC
-        .remove(b'!')
-        .remove(b'\'')
-        .remove(b'(')
-        .remove(b')')
-        .remove(b'*')
-        .remove(b'-')
-        .remove(b'.')
-        .remove(b'@')
-        .remove(b'_')
-        .remove(b'~');
-    let name = percent_encoding::utf8_percent_encode(name, &ASCII_SET);
-    registry_url
-      // Ensure that scoped package name percent encoding is lower cased
-      // to match npm.
-      .join(&name.to_string().replace("%2F", "%2f"))
-      .unwrap()
-  }
+}
+
+pub fn get_package_url(npmrc: &ResolvedNpmRc, name: &str) -> Url {
+  let registry_url = npmrc.get_registry_url(name);
+  // The '/' character in scoped package names "@scope/name" must be
+  // encoded for older third party registries. Newer registries and
+  // npm itself support both ways
+  //   - encoded: https://registry.npmjs.org/@rollup%2fplugin-json
+  //   - non-ecoded: https://registry.npmjs.org/@rollup/plugin-json
+  // To support as many third party registries as possible we'll
+  // always encode the '/' character.
+
+  // list of all characters used in npm packages:
+  //  !, ', (, ), *, -, ., /, [0-9], @, [A-Za-z], _, ~
+  const ASCII_SET: percent_encoding::AsciiSet =
+    percent_encoding::NON_ALPHANUMERIC
+      .remove(b'!')
+      .remove(b'\'')
+      .remove(b'(')
+      .remove(b')')
+      .remove(b'*')
+      .remove(b'-')
+      .remove(b'.')
+      .remove(b'@')
+      .remove(b'_')
+      .remove(b'~');
+  let name = percent_encoding::utf8_percent_encode(name, &ASCII_SET);
+  registry_url
+    // Ensure that scoped package name percent encoding is lower cased
+    // to match npm.
+    .join(&name.to_string().replace("%2F", "%2f"))
+    .unwrap()
 }
diff --git a/cli/npm/managed/mod.rs b/cli/npm/managed/mod.rs
index ec50a9c65a..d0880557fe 100644
--- a/cli/npm/managed/mod.rs
+++ b/cli/npm/managed/mod.rs
@@ -55,7 +55,7 @@ use super::CliNpmResolver;
 use super::InnerCliNpmResolverRef;
 use super::ResolvePkgFolderFromDenoReqError;
 
-mod cache;
+pub mod cache;
 mod registry;
 mod resolution;
 mod resolvers;
diff --git a/cli/npm/mod.rs b/cli/npm/mod.rs
index 53baaf77b4..f48f7a7405 100644
--- a/cli/npm/mod.rs
+++ b/cli/npm/mod.rs
@@ -8,10 +8,12 @@ use std::path::Path;
 use std::path::PathBuf;
 use std::sync::Arc;
 
+use common::maybe_auth_header_for_npm_registry;
 use dashmap::DashMap;
 use deno_ast::ModuleSpecifier;
 use deno_core::error::AnyError;
 use deno_core::serde_json;
+use deno_npm::npm_rc::ResolvedNpmRc;
 use deno_npm::registry::NpmPackageInfo;
 use deno_resolver::npm::ByonmNpmResolver;
 use deno_resolver::npm::ByonmResolvePkgFolderFromDenoReqError;
@@ -19,10 +21,10 @@ use deno_runtime::deno_node::NodeRequireResolver;
 use deno_runtime::ops::process::NpmProcessStateProvider;
 use deno_semver::package::PackageNv;
 use deno_semver::package::PackageReq;
+use managed::cache::registry_info::get_package_url;
 use node_resolver::NpmResolver;
 use thiserror::Error;
 
-use crate::args::npm_registry_url;
 use crate::file_fetcher::FileFetcher;
 
 pub use self::byonm::CliByonmNpmResolver;
@@ -115,14 +117,19 @@ pub struct NpmFetchResolver {
   nv_by_req: DashMap<PackageReq, Option<PackageNv>>,
   info_by_name: DashMap<String, Option<Arc<NpmPackageInfo>>>,
   file_fetcher: Arc<FileFetcher>,
+  npmrc: Arc<ResolvedNpmRc>,
 }
 
 impl NpmFetchResolver {
-  pub fn new(file_fetcher: Arc<FileFetcher>) -> Self {
+  pub fn new(
+    file_fetcher: Arc<FileFetcher>,
+    npmrc: Arc<ResolvedNpmRc>,
+  ) -> Self {
     Self {
       nv_by_req: Default::default(),
       info_by_name: Default::default(),
       file_fetcher,
+      npmrc,
     }
   }
 
@@ -157,11 +164,21 @@ impl NpmFetchResolver {
       return info.value().clone();
     }
     let fetch_package_info = || async {
-      let info_url = npm_registry_url().join(name).ok()?;
+      let info_url = get_package_url(&self.npmrc, name);
       let file_fetcher = self.file_fetcher.clone();
+      let registry_config = self.npmrc.get_registry_config(name);
+      // TODO(bartlomieju): this should error out, not use `.ok()`.
+      let maybe_auth_header =
+        maybe_auth_header_for_npm_registry(registry_config).ok()?;
       // spawn due to the lsp's `Send` requirement
       let file = deno_core::unsync::spawn(async move {
-        file_fetcher.fetch_bypass_permissions(&info_url).await.ok()
+        file_fetcher
+          .fetch_bypass_permissions_with_maybe_auth(
+            &info_url,
+            maybe_auth_header,
+          )
+          .await
+          .ok()
       })
       .await
       .ok()??;
diff --git a/cli/tools/registry/pm.rs b/cli/tools/registry/pm.rs
index 2060b9a13f..d1be901d67 100644
--- a/cli/tools/registry/pm.rs
+++ b/cli/tools/registry/pm.rs
@@ -367,10 +367,14 @@ pub async fn add(
     Default::default(),
     None,
   );
+
+  let npmrc = cli_factory.cli_options().unwrap().npmrc();
+
   deps_file_fetcher.set_download_log_level(log::Level::Trace);
   let deps_file_fetcher = Arc::new(deps_file_fetcher);
   let jsr_resolver = Arc::new(JsrFetchResolver::new(deps_file_fetcher.clone()));
-  let npm_resolver = Arc::new(NpmFetchResolver::new(deps_file_fetcher));
+  let npm_resolver =
+    Arc::new(NpmFetchResolver::new(deps_file_fetcher, npmrc.clone()));
 
   let mut selected_packages = Vec::with_capacity(add_flags.packages.len());
   let mut package_reqs = Vec::with_capacity(add_flags.packages.len());
diff --git a/tests/registry/npm-private3/@denotest3/basic/1.0.0/main.d.mts b/tests/registry/npm-private3/@denotest3/basic/1.0.0/main.d.mts
new file mode 100644
index 0000000000..29da1e6d7b
--- /dev/null
+++ b/tests/registry/npm-private3/@denotest3/basic/1.0.0/main.d.mts
@@ -0,0 +1,3 @@
+export declare function setValue(val: number): void;
+export declare function getValue(): number;
+export declare const url: string;
diff --git a/tests/registry/npm-private3/@denotest3/basic/1.0.0/main.mjs b/tests/registry/npm-private3/@denotest3/basic/1.0.0/main.mjs
new file mode 100644
index 0000000000..0a44f75859
--- /dev/null
+++ b/tests/registry/npm-private3/@denotest3/basic/1.0.0/main.mjs
@@ -0,0 +1,11 @@
+let value = 0;
+
+export function setValue(newValue) {
+  value = newValue;
+}
+
+export function getValue() {
+  return value;
+}
+
+export const url = import.meta.url;
diff --git a/tests/registry/npm-private3/@denotest3/basic/1.0.0/other.mjs b/tests/registry/npm-private3/@denotest3/basic/1.0.0/other.mjs
new file mode 100644
index 0000000000..00ed99da45
--- /dev/null
+++ b/tests/registry/npm-private3/@denotest3/basic/1.0.0/other.mjs
@@ -0,0 +1,3 @@
+export function hello() {
+    return "hello, world!";
+}
\ No newline at end of file
diff --git a/tests/registry/npm-private3/@denotest3/basic/1.0.0/package.json b/tests/registry/npm-private3/@denotest3/basic/1.0.0/package.json
new file mode 100644
index 0000000000..ce6ea33830
--- /dev/null
+++ b/tests/registry/npm-private3/@denotest3/basic/1.0.0/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "@denotest3/basic",
+  "version": "1.0.0",
+  "type": "module",
+  "main": "main.mjs",
+  "types": "main.d.mts"
+}
diff --git a/tests/specs/npm/npmrc_install_arg/.npmrc b/tests/specs/npm/npmrc_install_arg/.npmrc
new file mode 100644
index 0000000000..de3704b924
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/.npmrc
@@ -0,0 +1,2 @@
+@denotest:registry=http://localhost:4261/
+//localhost:4261/:_authToken=private-reg-token
diff --git a/tests/specs/npm/npmrc_install_arg/__test__.jsonc b/tests/specs/npm/npmrc_install_arg/__test__.jsonc
new file mode 100644
index 0000000000..f34cfe116a
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/__test__.jsonc
@@ -0,0 +1,23 @@
+{
+  "tempDir": true,
+  "tests": {
+    "deno_install_add": {
+      "steps": [{
+        "args": "install npm:@denotest/basic",
+        "output": "install.out"
+      }, {
+        "args": "run -A main.js",
+        "output": "main.out"
+      }]
+    },
+    "deno_add": {
+      "steps": [{
+        "args": "add npm:@denotest/basic",
+        "output": "add.out"
+      }, {
+        "args": "run -A main.js",
+        "output": "main.out"
+      }]
+    }
+  }
+}
diff --git a/tests/specs/npm/npmrc_install_arg/add.out b/tests/specs/npm/npmrc_install_arg/add.out
new file mode 100644
index 0000000000..11948e54d5
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/add.out
@@ -0,0 +1,4 @@
+Add npm:@denotest/basic@1.0.0
+Download http://localhost:4261/@denotest%2fbasic
+Download http://localhost:4261/@denotest/basic/1.0.0.tgz
+Initialize @denotest/basic@1.0.0
diff --git a/tests/specs/npm/npmrc_install_arg/install.out b/tests/specs/npm/npmrc_install_arg/install.out
new file mode 100644
index 0000000000..11948e54d5
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/install.out
@@ -0,0 +1,4 @@
+Add npm:@denotest/basic@1.0.0
+Download http://localhost:4261/@denotest%2fbasic
+Download http://localhost:4261/@denotest/basic/1.0.0.tgz
+Initialize @denotest/basic@1.0.0
diff --git a/tests/specs/npm/npmrc_install_arg/main.js b/tests/specs/npm/npmrc_install_arg/main.js
new file mode 100644
index 0000000000..e8ccf7611c
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/main.js
@@ -0,0 +1,5 @@
+import { getValue, setValue } from "@denotest/basic";
+
+console.log(getValue());
+setValue(42);
+console.log(getValue());
diff --git a/tests/specs/npm/npmrc_install_arg/main.out b/tests/specs/npm/npmrc_install_arg/main.out
new file mode 100644
index 0000000000..dcd912c89f
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/main.out
@@ -0,0 +1,2 @@
+0
+42
diff --git a/tests/specs/npm/npmrc_install_arg/package.json b/tests/specs/npm/npmrc_install_arg/package.json
new file mode 100644
index 0000000000..c1318b361a
--- /dev/null
+++ b/tests/specs/npm/npmrc_install_arg/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "npmrc_test",
+  "version": "0.0.1",
+  "dependencies": {}
+}
diff --git a/tests/specs/npm/npmrc_no_auth/.npmrc b/tests/specs/npm/npmrc_no_auth/.npmrc
new file mode 100644
index 0000000000..860a7c3d9a
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/.npmrc
@@ -0,0 +1 @@
+@denotest3:registry=http://localhost:4263/
diff --git a/tests/specs/npm/npmrc_no_auth/__test__.jsonc b/tests/specs/npm/npmrc_no_auth/__test__.jsonc
new file mode 100644
index 0000000000..efd04f0e46
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/__test__.jsonc
@@ -0,0 +1,23 @@
+{
+  "tempDir": true,
+  "tests": {
+    "deno_install_arg": {
+      "steps": [{
+        "args": "install npm:@denotest3/basic",
+        "output": "install.out"
+      }, {
+        "args": "run -A main.js",
+        "output": "main.out"
+      }]
+    },
+    "deno_add_arg": {
+      "steps": [{
+        "args": "add npm:@denotest3/basic",
+        "output": "add.out"
+      }, {
+        "args": "run -A main.js",
+        "output": "main.out"
+      }]
+    }
+  }
+}
diff --git a/tests/specs/npm/npmrc_no_auth/add.out b/tests/specs/npm/npmrc_no_auth/add.out
new file mode 100644
index 0000000000..31b34da13f
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/add.out
@@ -0,0 +1,4 @@
+Add npm:@denotest3/basic@1.0.0
+Download http://localhost:4263/@denotest3%2fbasic
+Download http://localhost:4263/@denotest3/basic/1.0.0.tgz
+Initialize @denotest3/basic@1.0.0
diff --git a/tests/specs/npm/npmrc_no_auth/install.out b/tests/specs/npm/npmrc_no_auth/install.out
new file mode 100644
index 0000000000..31b34da13f
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/install.out
@@ -0,0 +1,4 @@
+Add npm:@denotest3/basic@1.0.0
+Download http://localhost:4263/@denotest3%2fbasic
+Download http://localhost:4263/@denotest3/basic/1.0.0.tgz
+Initialize @denotest3/basic@1.0.0
diff --git a/tests/specs/npm/npmrc_no_auth/main.js b/tests/specs/npm/npmrc_no_auth/main.js
new file mode 100644
index 0000000000..22713bb0da
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/main.js
@@ -0,0 +1,5 @@
+import { getValue, setValue } from "@denotest3/basic";
+
+console.log(getValue());
+setValue(42);
+console.log(getValue());
diff --git a/tests/specs/npm/npmrc_no_auth/main.out b/tests/specs/npm/npmrc_no_auth/main.out
new file mode 100644
index 0000000000..dcd912c89f
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/main.out
@@ -0,0 +1,2 @@
+0
+42
diff --git a/tests/specs/npm/npmrc_no_auth/package.json b/tests/specs/npm/npmrc_no_auth/package.json
new file mode 100644
index 0000000000..dddaaac464
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "npmrc_test",
+  "version": "0.0.1",
+  "dependencies": {
+  }
+}
diff --git a/tests/specs/npm/npmrc_no_auth_install/.npmrc b/tests/specs/npm/npmrc_no_auth_install/.npmrc
new file mode 100644
index 0000000000..860a7c3d9a
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth_install/.npmrc
@@ -0,0 +1 @@
+@denotest3:registry=http://localhost:4263/
diff --git a/tests/specs/npm/npmrc_no_auth_install/__test__.jsonc b/tests/specs/npm/npmrc_no_auth_install/__test__.jsonc
new file mode 100644
index 0000000000..56a598e3b9
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth_install/__test__.jsonc
@@ -0,0 +1,14 @@
+{
+  "tempDir": true,
+  "tests": {
+    "deno_install_arg": {
+      "steps": [{
+        "args": "install",
+        "output": "install.out"
+      }, {
+        "args": "run -A main.js",
+        "output": "main.out"
+      }]
+    }
+  }
+}
diff --git a/tests/specs/npm/npmrc_no_auth_install/install.out b/tests/specs/npm/npmrc_no_auth_install/install.out
new file mode 100644
index 0000000000..b82747af79
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth_install/install.out
@@ -0,0 +1,3 @@
+Download http://localhost:4263/@denotest3%2fbasic
+Download http://localhost:4263/@denotest3/basic/1.0.0.tgz
+Initialize @denotest3/basic@1.0.0
diff --git a/tests/specs/npm/npmrc_no_auth_install/main.js b/tests/specs/npm/npmrc_no_auth_install/main.js
new file mode 100644
index 0000000000..22713bb0da
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth_install/main.js
@@ -0,0 +1,5 @@
+import { getValue, setValue } from "@denotest3/basic";
+
+console.log(getValue());
+setValue(42);
+console.log(getValue());
diff --git a/tests/specs/npm/npmrc_no_auth_install/main.out b/tests/specs/npm/npmrc_no_auth_install/main.out
new file mode 100644
index 0000000000..dcd912c89f
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth_install/main.out
@@ -0,0 +1,2 @@
+0
+42
diff --git a/tests/specs/npm/npmrc_no_auth_install/package.json b/tests/specs/npm/npmrc_no_auth_install/package.json
new file mode 100644
index 0000000000..2d4fb15bae
--- /dev/null
+++ b/tests/specs/npm/npmrc_no_auth_install/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "npmrc_test",
+  "version": "0.0.1",
+  "dependencies": {
+    "@denotest3/basic": "1.0.0"
+  }
+}
diff --git a/tests/util/server/src/lib.rs b/tests/util/server/src/lib.rs
index 88e8287e08..e4a2cc02e3 100644
--- a/tests/util/server/src/lib.rs
+++ b/tests/util/server/src/lib.rs
@@ -307,7 +307,7 @@ async fn get_tcp_listener_stream(
   futures::stream::select_all(listeners)
 }
 
-pub const TEST_SERVERS_COUNT: usize = 30;
+pub const TEST_SERVERS_COUNT: usize = 32;
 
 #[derive(Default)]
 struct HttpServerCount {
@@ -360,6 +360,7 @@ impl Default for HttpServerStarter {
     let mut ready_count = 0;
     for maybe_line in lines {
       if let Ok(line) = maybe_line {
+        eprintln!("LINE: {}", line);
         if line.starts_with("ready:") {
           ready_count += 1;
         }
diff --git a/tests/util/server/src/npm.rs b/tests/util/server/src/npm.rs
index f1c341738a..4b17b95f72 100644
--- a/tests/util/server/src/npm.rs
+++ b/tests/util/server/src/npm.rs
@@ -18,6 +18,7 @@ use crate::PathRef;
 
 pub const DENOTEST_SCOPE_NAME: &str = "@denotest";
 pub const DENOTEST2_SCOPE_NAME: &str = "@denotest2";
+pub const DENOTEST3_SCOPE_NAME: &str = "@denotest3";
 
 pub static PUBLIC_TEST_NPM_REGISTRY: Lazy<TestNpmRegistry> = Lazy::new(|| {
   TestNpmRegistry::new(
@@ -54,6 +55,18 @@ pub static PRIVATE_TEST_NPM_REGISTRY_2: Lazy<TestNpmRegistry> =
     )
   });
 
+pub static PRIVATE_TEST_NPM_REGISTRY_3: Lazy<TestNpmRegistry> =
+  Lazy::new(|| {
+    TestNpmRegistry::new(
+      NpmRegistryKind::Private,
+      &format!(
+        "http://localhost:{}",
+        crate::servers::PRIVATE_NPM_REGISTRY_3_PORT
+      ),
+      "npm-private3",
+    )
+  });
+
 pub enum NpmRegistryKind {
   Public,
   Private,
@@ -90,6 +103,7 @@ impl TestNpmRegistry {
   }
 
   pub fn root_dir(&self) -> PathRef {
+    eprintln!("root {}", self.local_path);
     tests_path().join("registry").join(&self.local_path)
   }
 
@@ -106,6 +120,7 @@ impl TestNpmRegistry {
   }
 
   pub fn registry_file(&self, name: &str) -> Result<Option<Vec<u8>>> {
+    eprintln!("registry file {}", name);
     self.get_package_property(name, |p| p.registry_file.as_bytes().to_vec())
   }
 
@@ -123,6 +138,7 @@ impl TestNpmRegistry {
     package_name: &str,
     func: impl FnOnce(&CustomNpmPackage) -> TResult,
   ) -> Result<Option<TResult>> {
+    eprintln!("get package property {}", package_name);
     // it's ok if multiple threads race here as they will do the same work twice
     if !self.cache.lock().contains_key(package_name) {
       match get_npm_package(&self.hostname, &self.local_path, package_name)? {
@@ -139,6 +155,7 @@ impl TestNpmRegistry {
     &self,
     uri_path: &'s str,
   ) -> Option<(&'s str, &'s str)> {
+    eprintln!("GEETT {}", uri_path);
     let prefix1 = format!("/{}/", DENOTEST_SCOPE_NAME);
     let prefix2 = format!("/{}%2f", DENOTEST_SCOPE_NAME);
 
@@ -161,6 +178,17 @@ impl TestNpmRegistry {
       return Some((DENOTEST2_SCOPE_NAME, package_name_with_path));
     }
 
+    let prefix1 = format!("/{}/", DENOTEST3_SCOPE_NAME);
+    let prefix2 = format!("/{}%2f", DENOTEST3_SCOPE_NAME);
+
+    let maybe_package_name_with_path = uri_path
+      .strip_prefix(&prefix1)
+      .or_else(|| uri_path.strip_prefix(&prefix2));
+
+    if let Some(package_name_with_path) = maybe_package_name_with_path {
+      return Some((DENOTEST3_SCOPE_NAME, package_name_with_path));
+    }
+
     None
   }
 }
@@ -170,6 +198,10 @@ fn get_npm_package(
   local_path: &str,
   package_name: &str,
 ) -> Result<Option<CustomNpmPackage>> {
+  eprintln!(
+    "get npm package {} {} {}",
+    registry_hostname, local_path, package_name
+  );
   let registry_hostname = if package_name == "@denotest/tarballs-privateserver2"
   {
     "http://localhost:4262"
diff --git a/tests/util/server/src/servers/mod.rs b/tests/util/server/src/servers/mod.rs
index 3e18aafce4..3a9c440104 100644
--- a/tests/util/server/src/servers/mod.rs
+++ b/tests/util/server/src/servers/mod.rs
@@ -91,6 +91,7 @@ const PROVENANCE_MOCK_SERVER_PORT: u16 = 4251;
 pub(crate) const PUBLIC_NPM_REGISTRY_PORT: u16 = 4260;
 pub(crate) const PRIVATE_NPM_REGISTRY_1_PORT: u16 = 4261;
 pub(crate) const PRIVATE_NPM_REGISTRY_2_PORT: u16 = 4262;
+pub(crate) const PRIVATE_NPM_REGISTRY_3_PORT: u16 = 4263;
 
 // Use the single-threaded scheduler. The hyper server is used as a point of
 // comparison for the (single-threaded!) benchmarks in cli/bench. We're not
@@ -143,6 +144,8 @@ pub async fn run_all_servers() {
     npm_registry::private_npm_registry1(PRIVATE_NPM_REGISTRY_1_PORT);
   let private_npm_registry_2_server_futs =
     npm_registry::private_npm_registry2(PRIVATE_NPM_REGISTRY_2_PORT);
+  let private_npm_registry_3_server_futs =
+    npm_registry::private_npm_registry3(PRIVATE_NPM_REGISTRY_3_PORT);
 
   let mut futures = vec![
     redirect_server_fut.boxed_local(),
@@ -173,6 +176,7 @@ pub async fn run_all_servers() {
   futures.extend(npm_registry_server_futs);
   futures.extend(private_npm_registry_1_server_futs);
   futures.extend(private_npm_registry_2_server_futs);
+  futures.extend(private_npm_registry_3_server_futs);
 
   assert_eq!(futures.len(), TEST_SERVERS_COUNT);
 
diff --git a/tests/util/server/src/servers/npm_registry.rs b/tests/util/server/src/servers/npm_registry.rs
index acbd9cab48..4ada468fac 100644
--- a/tests/util/server/src/servers/npm_registry.rs
+++ b/tests/util/server/src/servers/npm_registry.rs
@@ -56,6 +56,14 @@ pub fn private_npm_registry2(port: u16) -> Vec<LocalBoxFuture<'static, ()>> {
   )
 }
 
+pub fn private_npm_registry3(port: u16) -> Vec<LocalBoxFuture<'static, ()>> {
+  run_npm_server(
+    port,
+    "npm private registry server error",
+    private_npm_registry3_handler,
+  )
+}
+
 fn run_npm_server<F, S>(
   port: u16,
   error_msg: &'static str,
@@ -141,6 +149,13 @@ async fn private_npm_registry2_handler(
   handle_req_for_registry(req, &npm::PRIVATE_TEST_NPM_REGISTRY_2).await
 }
 
+async fn private_npm_registry3_handler(
+  req: Request<hyper::body::Incoming>,
+) -> Result<Response<UnsyncBoxBody<Bytes, Infallible>>, anyhow::Error> {
+  // No auth for this registry
+  handle_req_for_registry(req, &npm::PRIVATE_TEST_NPM_REGISTRY_3).await
+}
+
 async fn handle_req_for_registry(
   req: Request<Incoming>,
   test_npm_registry: &npm::TestNpmRegistry,