diff --git a/.changeset/mdn-type-link-locale.md b/.changeset/mdn-type-link-locale.md
new file mode 100644
index 00000000..24e65722
--- /dev/null
+++ b/.changeset/mdn-type-link-locale.md
@@ -0,0 +1,9 @@
+---
+'@node-core/doc-kit': patch
+---
+
+Pin the `en-US` locale on builtin MDN type links that carry a hash fragment
+(e.g. `number`, `string`, `any`). Locale-less MDN URLs redirect to the
+visitor's preferred language, where heading anchor IDs are translated, so the
+original fragment (e.g. `#number_type`) no longer matches any anchor on the
+redirected page and the link fails to jump to the target section.
diff --git a/packages/core/src/generators/metadata/maps/builtin.json b/packages/core/src/generators/metadata/maps/builtin.json
index 5601f242..3823ed48 100644
--- a/packages/core/src/generators/metadata/maps/builtin.json
+++ b/packages/core/src/generators/metadata/maps/builtin.json
@@ -1,16 +1,16 @@
 {
   "asynciterable": "https://tc39.github.io/ecma262/#sec-asynciterable-interface",
-  "iterable": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterable_protocol",
+  "iterable": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterable_protocol",
   "void": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Operators/void",
   "module namespace object": "https://tc39.github.io/ecma262/#sec-module-namespace-exotic-objects",
-  "null": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#null_type",
-  "undefined": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#undefined_type",
-  "boolean": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#boolean_type",
-  "number": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#number_type",
-  "bigint": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#bigint_type",
-  "string": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#string_type",
-  "symbol": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#symbol_type",
-  "integer": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#number_type",
-  "any": "https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#Data_types",
+  "null": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#null_type",
+  "undefined": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#undefined_type",
+  "boolean": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#boolean_type",
+  "number": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#number_type",
+  "bigint": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#bigint_type",
+  "string": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type",
+  "symbol": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#symbol_type",
+  "integer": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#number_type",
+  "any": "https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Data_types",
   "this": "https://developer.mozilla.org/docs/Web/JavaScript/Reference/Operators/this"
 }
diff --git a/packages/core/src/generators/metadata/utils/__tests__/resolveTypes.test.mjs b/packages/core/src/generators/metadata/utils/__tests__/resolveTypes.test.mjs
index bd25c4ac..3832e124 100644
--- a/packages/core/src/generators/metadata/utils/__tests__/resolveTypes.test.mjs
+++ b/packages/core/src/generators/metadata/utils/__tests__/resolveTypes.test.mjs
@@ -125,7 +125,7 @@ describe('resolveTypeAnnotations', () => {
         ],
         [
           'string',
-          'https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#string_type',
+          'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type',
         ],
         ['Buffer', 'buffer.html#buffer'],
       ]
@@ -135,7 +135,7 @@ describe('resolveTypeAnnotations', () => {
 
   it('resolves every annotation in a nested tree', () => {
     const STRING_URL =
-      'https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#string_type';
+      'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type';
 
     // Two per paragraph: a visitor that skips siblings still reaches the first
     const nodes = ['string', 'HTTP/2 Headers Object', 'string', 'string'].map(
diff --git a/packages/core/src/generators/metadata/utils/__tests__/transformers.test.mjs b/packages/core/src/generators/metadata/utils/__tests__/transformers.test.mjs
index b6c3355d..1b9e95e5 100644
--- a/packages/core/src/generators/metadata/utils/__tests__/transformers.test.mjs
+++ b/packages/core/src/generators/metadata/utils/__tests__/transformers.test.mjs
@@ -11,7 +11,7 @@ describe('lookupTypeName', () => {
   it('resolves JavaScript primitives from the built-in map', () => {
     strictEqual(
       lookupTypeName('string'),
-      'https://developer.mozilla.org/docs/Web/JavaScript/Data_structures#string_type'
+      'https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#string_type'
     );
   });