src/Normalizer/ConfigEntityNormalizer.php       |  4 ++--
 src/ResourceType/ResourceType.php               | 16 ++++++++++++++--
 tests/src/Functional/ActionTest.php             |  4 +---
 tests/src/Functional/FieldStorageConfigTest.php |  2 +-
 tests/src/Functional/NodeTypeTest.php           |  2 +-
 tests/src/Functional/WorkflowTest.php           |  2 +-
 6 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/Normalizer/ConfigEntityNormalizer.php b/src/Normalizer/ConfigEntityNormalizer.php
index 44fb54c..1508ccb 100644
--- a/src/Normalizer/ConfigEntityNormalizer.php
+++ b/src/Normalizer/ConfigEntityNormalizer.php
@@ -49,8 +49,8 @@ class ConfigEntityNormalizer extends EntityNormalizer {
     //   mandatory "id" attribute in JSON API)
     // @see http://jsonapi.org/format/#document-resource-identifier-objects
     $id_field_name = $entity->getEntityType()->getKey('id');
-    unset($enabled_public_fields[$id_field_name]);
-    unset($enabled_public_fields['uuid']);
+    unset($enabled_public_fields[$resource_type->getPublicName($id_field_name)]);
+    unset($enabled_public_fields[$resource_type->getPublicName('uuid')]);
 
     return $enabled_public_fields;
   }
diff --git a/src/ResourceType/ResourceType.php b/src/ResourceType/ResourceType.php
index 3dc15b2..e45ac8e 100644
--- a/src/ResourceType/ResourceType.php
+++ b/src/ResourceType/ResourceType.php
@@ -118,7 +118,14 @@ class ResourceType {
    *   The public field name.
    */
   public function getPublicName($field_name) {
-    // By default the entity field name is the public field name.
+    // By default the entity field name is the public field name. Unless the
+    // public name is "id" or "type" — then they're prefixed with an underscore,
+    // because these are reserved by the JSON API spec.
+    // @see http://jsonapi.org/format/#document-resource-object-fields
+    if ($field_name === 'id' || $field_name === 'type') {
+      return "_$field_name";
+    }
+
     return $field_name;
   }
 
@@ -132,7 +139,12 @@ class ResourceType {
    *   The internal field name as defined in the entity.
    */
   public function getInternalName($field_name) {
-    // By default the entity field name is the public field name.
+    // By default the entity field name is the public field name. Unless: see
+    // ::getPublicName().
+    if ($field_name === '_id' || $field_name === '_type') {
+      return substr($field_name, 1);
+    }
+
     return $field_name;
   }
 
diff --git a/tests/src/Functional/ActionTest.php b/tests/src/Functional/ActionTest.php
index cc57864..e7ef223 100644
--- a/tests/src/Functional/ActionTest.php
+++ b/tests/src/Functional/ActionTest.php
@@ -91,13 +91,11 @@ class ActionTest extends ResourceTestBase {
             'config' => ['user.role.anonymous'],
             'module' => ['user'],
           ],
-          'id' => 'user_add_role_action.anonymous',
           'label' => 'Add the anonymous role to the selected users',
           'langcode' => 'en',
           'plugin' => 'user_add_role_action',
           'status' => TRUE,
-          'type' => 'user',
-          'uuid' => $this->entity->uuid(),
+          '_type' => 'user',
         ],
       ],
     ];
diff --git a/tests/src/Functional/FieldStorageConfigTest.php b/tests/src/Functional/FieldStorageConfigTest.php
index 2bf7bf7..cfaaa8b 100644
--- a/tests/src/Functional/FieldStorageConfigTest.php
+++ b/tests/src/Functional/FieldStorageConfigTest.php
@@ -95,7 +95,7 @@ class FieldStorageConfigTest extends ResourceTestBase {
           'settings' => [],
           'status' => TRUE,
           'translatable' => TRUE,
-          'type' => 'boolean',
+          '_type' => 'boolean',
         ],
       ],
     ];
diff --git a/tests/src/Functional/NodeTypeTest.php b/tests/src/Functional/NodeTypeTest.php
index c10fa0e..46bb7d2 100644
--- a/tests/src/Functional/NodeTypeTest.php
+++ b/tests/src/Functional/NodeTypeTest.php
@@ -90,7 +90,7 @@ class NodeTypeTest extends ResourceTestBase {
           'new_revision' => TRUE,
           'preview_mode' => 1,
           'status' => TRUE,
-          'type' => 'camelids',
+          '_type' => 'camelids',
         ],
       ],
     ];
diff --git a/tests/src/Functional/WorkflowTest.php b/tests/src/Functional/WorkflowTest.php
index 0766a80..e5e6923 100644
--- a/tests/src/Functional/WorkflowTest.php
+++ b/tests/src/Functional/WorkflowTest.php
@@ -94,7 +94,7 @@ class WorkflowTest extends ResourceTestBase {
           'label' => 'REST Worklow',
           'langcode' => 'en',
           'status' => TRUE,
-          'type' => 'workflow_type_complex_test',
+          '_type' => 'workflow_type_complex_test',
           'type_settings' => [
             'states' => [
               'draft' => [