diff --git a/src/npm/use-npm-environment.ts b/src/npm/use-npm-environment.ts
index d6a0da9..ac0b543 100644
--- a/src/npm/use-npm-environment.ts
+++ b/src/npm/use-npm-environment.ts
@@ -29,22 +29,21 @@ export async function useNpmEnvironment<TReturn>(
   task: NpmCliTask<TReturn>
 ): Promise<TReturn> {
   const { registry, token, logger, temporaryDirectory } = options;
-  const npmrcDirectory = await fs.mkdtemp(
-    path.join(temporaryDirectory, "npm-publish-")
-  );
-  const npmrc = path.join(npmrcDirectory, ".npmrc");
-  const environment = {
-    NODE_AUTH_TOKEN: token,
-    npm_config_userconfig: npmrc,
-  };
-
+  const { host, origin, pathname } = registry;
+  const pathnameWithSlash = pathname.endsWith("/") ? pathname : `${pathname}/`;
   const config = [
     "; created by jsdevtools/npm-publish",
-    `//${registry.host}${registry.pathname}:_authToken=\${NODE_AUTH_TOKEN}`,
-    `registry=${registry.href}`,
+    `//${host}${pathnameWithSlash}:_authToken=\${NODE_AUTH_TOKEN}`,
+    `registry=${origin}${pathnameWithSlash}`,
     "",
   ].join(os.EOL);
 
+  const npmrcDirectory = await fs.mkdtemp(
+    path.join(temporaryDirectory, "npm-publish-")
+  );
+  const npmrc = path.join(npmrcDirectory, ".npmrc");
+  const environment = { NODE_AUTH_TOKEN: token, npm_config_userconfig: npmrc };
+
   await fs.writeFile(npmrc, config, "utf8");
 
   logger?.debug?.(`Temporary .npmrc created at ${npmrc}\n${config}`);