@@ -11,6 +11,8 @@
 #include "Runtime.h"
 #include "StructuredSerialization.h"
 #include "TextEncoding.h"
+#include "URLImpl.h"
+#include "URLSearchParamsImpl.h"
 #include "Worker.h"
 
 using namespace v8;
@@ -25,6 +27,7 @@ constexpr const char* kNodePrefix = "node:";
 // Defined below, each next to the natives it gathers.
 MaybeLocal<Object> NsModuleBinding(Local<Context> context);
 MaybeLocal<Object> NsRuntimeBinding(Local<Context> context);
+MaybeLocal<Object> NsUrlBinding(Local<Context> context);
 MaybeLocal<Object> NsUtilBinding(Local<Context> context);
 MaybeLocal<Object> NsWorkerThreadsBinding(Local<Context> context);
 
@@ -47,6 +50,7 @@ struct Registration {
 constexpr Registration kRegistry[] = {
     {"ns:module", BuiltinId::kNsModule, NsModuleBinding},
     {"ns:runtime", BuiltinId::kNsRuntime, NsRuntimeBinding},
+    {"ns:url", BuiltinId::kNsUrl, NsUrlBinding},
     {"ns:util", BuiltinId::kNsUtil, NsUtilBinding},
     {"ns:worker_threads", BuiltinId::kNsWorkerThreads, NsWorkerThreadsBinding},
     {"node:module", BuiltinId::kNodeModule, nullptr},
@@ -200,6 +204,27 @@ MaybeLocal<Object> NsRuntimeBinding(Local<Context> context) {
   return binding;
 }
 
+// URL and URLSearchParams for ns:url: the context's own, from the templates
+// their Init installed, rather than whatever the globals name by the time the
+// module is first required.
+MaybeLocal<Object> NsUrlBinding(Local<Context> context) {
+  Isolate* isolate = v8::Isolate::GetCurrent();
+  Local<Object> binding = Object::New(isolate);
+  Local<v8::Function> url;
+  Local<v8::Function> searchParams;
+  if (!URLImpl::Constructor(context).ToLocal(&url) ||
+      !URLSearchParamsImpl::Constructor(context).ToLocal(&searchParams) ||
+      !binding->Set(context, tns::ToV8String(isolate, "URL"), url)
+           .FromMaybe(false) ||
+      !binding
+           ->Set(context, tns::ToV8String(isolate, "URLSearchParams"),
+                 searchParams)
+           .FromMaybe(false)) {
+    return MaybeLocal<Object>();
+  }
+  return binding;
+}
+
 // The Worker constructor for ns:worker_threads: the context's own, from the
 // template Worker::Init installed, rather than whatever `globalThis.Worker`
 // names by the time the module is first required.
 
@@ -4,12 +4,24 @@
 
 #include "URLImpl.h"
 
+#include "Caches.h"
 #include "Helpers.h"
 #include "ModuleBinding.hpp"
 
 using namespace tns;
 using namespace ada;
 
+namespace {
+
+// The constructor template Init put on the global template. A template's
+// function is cached per context, so instantiating it again yields the very
+// function the global was created with.
+struct URLConstructorState {
+  v8::Global<v8::FunctionTemplate> constructor;
+};
+
+}  // namespace
+
 URLImpl::URLImpl(url_aggregator url) : url_(url) {}
 
 void URLImpl::Init(v8::Isolate* isolate,
@@ -18,6 +30,20 @@ void URLImpl::Init(v8::Isolate* isolate,
 
   v8::Local<v8::String> urlPropertyName = ToV8String(isolate, "URL");
   globalTemplate->Set(urlPropertyName, URLTemplate);
+
+  if (auto* state = Caches::StateFor<URLConstructorState>(isolate)) {
+    state->constructor.Reset(isolate, URLTemplate);
+  }
+}
+
+v8::MaybeLocal<v8::Function> URLImpl::Constructor(
+    v8::Local<v8::Context> context) {
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  auto* state = Caches::StateFor<URLConstructorState>(isolate);
+  if (state == nullptr || state->constructor.IsEmpty()) {
+    return v8::MaybeLocal<v8::Function>();
+  }
+  return state->constructor.Get(isolate)->GetFunction(context);
 }
 
 URLImpl* URLImpl::GetPointer(v8::Local<v8::Object> object) {
 
@@ -21,6 +21,13 @@ class URLImpl : public IsolateTracked {
   static void Init(v8::Isolate* isolate,
                    v8::Local<v8::ObjectTemplate> globalTemplate);
 
+  // The URL constructor of `context`: the function Init's template produces
+  // for it, which is the object the global of that name was created with,
+  // whatever `globalThis.URL` names by now. Empty before Init has run for the
+  // isolate.
+  static v8::MaybeLocal<v8::Function> Constructor(
+      v8::Local<v8::Context> context);
+
   static URLImpl* GetPointer(v8::Local<v8::Object> object);
 
   static v8::Local<v8::FunctionTemplate> GetCtor(v8::Isolate* isolate);
 
@@ -4,12 +4,24 @@
 
 #include "URLSearchParamsImpl.h"
 
+#include "Caches.h"
 #include "Helpers.h"
 #include "ModuleBinding.hpp"
 
 using namespace ada;
 
 namespace tns {
+
+namespace {
+
+// The constructor template Init put on the global template; see
+// URLConstructorState in URLImpl.cpp.
+struct URLSearchParamsConstructorState {
+  v8::Global<v8::FunctionTemplate> constructor;
+};
+
+}  // namespace
+
 URLSearchParamsImpl::URLSearchParamsImpl(ada::url_search_params params)
     : params_(params) {}
 
@@ -20,6 +32,21 @@ void URLSearchParamsImpl::Init(v8::Isolate* isolate,
   v8::Local<v8::String> urlSearchParamsPropertyName =
       ToV8String(isolate, "URLSearchParams");
   globalTemplate->Set(urlSearchParamsPropertyName, URLSearchParamsTemplate);
+
+  if (auto* state =
+          Caches::StateFor<URLSearchParamsConstructorState>(isolate)) {
+    state->constructor.Reset(isolate, URLSearchParamsTemplate);
+  }
+}
+
+v8::MaybeLocal<v8::Function> URLSearchParamsImpl::Constructor(
+    v8::Local<v8::Context> context) {
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  auto* state = Caches::StateFor<URLSearchParamsConstructorState>(isolate);
+  if (state == nullptr || state->constructor.IsEmpty()) {
+    return v8::MaybeLocal<v8::Function>();
+  }
+  return state->constructor.Get(isolate)->GetFunction(context);
 }
 
 URLSearchParamsImpl* URLSearchParamsImpl::GetPointer(
 
@@ -22,6 +22,10 @@ class URLSearchParamsImpl : public IsolateTracked {
   static void Init(v8::Isolate* isolate,
                    v8::Local<v8::ObjectTemplate> globalTemplate);
 
+  // The URLSearchParams constructor of `context`, as URLImpl::Constructor.
+  static v8::MaybeLocal<v8::Function> Constructor(
+      v8::Local<v8::Context> context);
+
   static void Ctor(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   static void Append(const v8::FunctionCallbackInfo<v8::Value>& args);
 
@@ -1,104 +1,16 @@
 "use strict";
 
-// The `node:url` compatibility shim: the two path/URL converters
-// (docs/ns-builtin-modules.md). Parsing goes through the URL intrinsic rather
-// than a hand-rolled scan, so authority normalization (`file://localhost/x`
-// has no host, per the URL spec), percent-decoding and path canonicalization
-// all follow the spec instead of an approximation.
+// The `node:url` compatibility shim over `ns:url` (docs/ns-builtin-modules.md).
+// The two surfaces coincide today, so this only re-exports; any adaptation to
+// Node's API belongs here, never in the standard module.
 
-const {
-  decodeURIComponent,
-  ObjectFreeze,
-  StringPrototypeCharCodeAt,
-  StringPrototypeStartsWith,
-  TypeError,
-  URL,
-} = primordials;
-
-const INVALID_ARG =
-  'The "path" argument must be of type string or an instance of URL.';
-
-function toUrl(input) {
-  let href;
-  if (typeof input === "string") {
-    href = input;
-  } else if (input !== null && typeof input === "object" &&
-             typeof input.href === "string") {
-    // Duck-typed so a URL from another realm still works.
-    href = input.href;
-  } else {
-    throw new TypeError(INVALID_ARG);
-  }
-
-  try {
-    return new URL(href);
-  } catch {
-    throw new TypeError(INVALID_ARG);
-  }
-}
-
-function fileURLToPath(input) {
-  const url = toUrl(input);
-
-  if (url.protocol !== "file:") {
-    throw new TypeError("The URL must be of scheme file");
-  }
-  // The URL parser already folded a "localhost" authority to the empty host,
-  // so anything left here is a real remote host and names no local file.
-  if (url.hostname !== "") {
-    throw new TypeError('File URL host must be "localhost" or empty');
-  }
-
-  // `pathname` carries neither the query nor the fragment.
-  const pathname = url.pathname;
-  for (let i = 0; i < pathname.length; i++) {
-    if (pathname[i] !== "%") {
-      continue;
-    }
-    // %2F would decode to a separator and silently change the path's shape.
-    const third = StringPrototypeCharCodeAt(pathname, i + 2) | 0x20;
-    if (pathname[i + 1] === "2" && third === 102 /* 'f' */) {
-      throw new TypeError("File URL path must not include encoded / characters");
-    }
-  }
+const { ObjectFreeze } = primordials;
+const { URL, URLSearchParams, fileURLToPath, pathToFileURL } =
+  require("ns:url");
 
-  return decodeURIComponent(pathname);
-}
-
-const kHexDigits = "0123456789ABCDEF";
-
-// Percent-encode everything the URL parser would otherwise read as syntax (or
-// reject), leaving `/` as the separator it is. Non-ASCII is left alone: the
-// parser UTF-8 encodes it correctly on its own.
-function encodePathChars(filepath) {
-  let encoded = "";
-  for (let i = 0; i < filepath.length; i++) {
-    const char = filepath[i];
-    const code = StringPrototypeCharCodeAt(filepath, i);
-    const mustEncode =
-      code < 0x21 || code === 0x7f || char === "%" || char === "?" ||
-      char === "#" || char === "\\" || char === '"' || char === "<" ||
-      char === ">" || char === "`" || char === "{" || char === "}";
-    if (mustEncode) {
-      encoded += "%" + kHexDigits[(code >> 4) & 0xf] + kHexDigits[code & 0xf];
-    } else {
-      encoded += char;
-    }
-  }
-  return encoded;
-}
-
-function pathToFileURL(filepath) {
-  if (typeof filepath !== "string") {
-    throw new TypeError('The "path" argument must be of type string.');
-  }
-  // Node resolves a relative path against the process working directory; there
-  // is no such thing here, so a relative path has no single correct answer.
-  if (!StringPrototypeStartsWith(filepath, "/")) {
-    throw new TypeError('The "path" argument must be an absolute path.');
-  }
-
-  return new URL("file://" + encodePathChars(filepath));
-}
-
-module.exports = ObjectFreeze({ fileURLToPath, pathToFileURL });
+module.exports = ObjectFreeze({
+  URL,
+  URLSearchParams,
+  fileURLToPath,
+  pathToFileURL,
+});
@@ -0,0 +1,111 @@
+"use strict";
+
+// The `ns:url` builtin module: the runtime's own URL and URLSearchParams, the
+// very functions the globals of those names were created with, and the two
+// path/URL converters. See docs/ns-builtin-modules.md for the contract.
+//
+// The converters parse through URL rather than a hand-rolled scan, so
+// authority normalization (`file://localhost/x` has no host, per the URL
+// spec), percent-decoding and path canonicalization all follow the spec
+// instead of an approximation.
+
+const { URL, URLSearchParams } = binding;
+const {
+  decodeURIComponent,
+  ObjectFreeze,
+  StringPrototypeCharCodeAt,
+  StringPrototypeStartsWith,
+  TypeError,
+} = primordials;
+
+const INVALID_ARG =
+  'The "path" argument must be of type string or an instance of URL.';
+
+function toUrl(input) {
+  let href;
+  if (typeof input === "string") {
+    href = input;
+  } else if (input !== null && typeof input === "object" &&
+             typeof input.href === "string") {
+    // Duck-typed so a URL from another realm still works.
+    href = input.href;
+  } else {
+    throw new TypeError(INVALID_ARG);
+  }
+
+  try {
+    return new URL(href);
+  } catch {
+    throw new TypeError(INVALID_ARG);
+  }
+}
+
+function fileURLToPath(input) {
+  const url = toUrl(input);
+
+  if (url.protocol !== "file:") {
+    throw new TypeError("The URL must be of scheme file");
+  }
+  // The URL parser already folded a "localhost" authority to the empty host,
+  // so anything left here is a real remote host and names no local file.
+  if (url.hostname !== "") {
+    throw new TypeError('File URL host must be "localhost" or empty');
+  }
+
+  // `pathname` carries neither the query nor the fragment.
+  const pathname = url.pathname;
+  for (let i = 0; i < pathname.length; i++) {
+    if (pathname[i] !== "%") {
+      continue;
+    }
+    // %2F would decode to a separator and silently change the path's shape.
+    const third = StringPrototypeCharCodeAt(pathname, i + 2) | 0x20;
+    if (pathname[i + 1] === "2" && third === 102 /* 'f' */) {
+      throw new TypeError("File URL path must not include encoded / characters");
+    }
+  }
+
+  return decodeURIComponent(pathname);
+}
+
+const kHexDigits = "0123456789ABCDEF";
+
+// Percent-encode everything the URL parser would otherwise read as syntax (or
+// reject), leaving `/` as the separator it is. Non-ASCII is left alone: the
+// parser UTF-8 encodes it correctly on its own.
+function encodePathChars(filepath) {
+  let encoded = "";
+  for (let i = 0; i < filepath.length; i++) {
+    const char = filepath[i];
+    const code = StringPrototypeCharCodeAt(filepath, i);
+    const mustEncode =
+      code < 0x21 || code === 0x7f || char === "%" || char === "?" ||
+      char === "#" || char === "\\" || char === '"' || char === "<" ||
+      char === ">" || char === "`" || char === "{" || char === "}";
+    if (mustEncode) {
+      encoded += "%" + kHexDigits[(code >> 4) & 0xf] + kHexDigits[code & 0xf];
+    } else {
+      encoded += char;
+    }
+  }
+  return encoded;
+}
+
+function pathToFileURL(filepath) {
+  if (typeof filepath !== "string") {
+    throw new TypeError('The "path" argument must be of type string.');
+  }
+  // Node resolves a relative path against the process working directory; there
+  // is no such thing here, so a relative path has no single correct answer.
+  if (!StringPrototypeStartsWith(filepath, "/")) {
+    throw new TypeError('The "path" argument must be an absolute path.');
+  }
+
+  return new URL("file://" + encodePathChars(filepath));
+}
+
+exports.URL = URL;
+exports.URLSearchParams = URLSearchParams;
+exports.fileURLToPath = fileURLToPath;
+exports.pathToFileURL = pathToFileURL;
+ObjectFreeze(exports);