diff --git a/src/lib/openapi/PropertySchema.php b/src/lib/openapi/PropertySchema.php
index 56d6df7a..227e2011 100644
--- a/src/lib/openapi/PropertySchema.php
+++ b/src/lib/openapi/PropertySchema.php
@@ -273,8 +273,10 @@ public function getSelfTargetProperty():?PropertySchema
     public function isRefPointerToSchema():bool
     {
         return $this->refPointer &&
-            ((strpos($this->refPointer, self::REFERENCE_PATH) === 0) ||
-                (str_ends_with($this->uri, '.yml')) || (str_ends_with($this->uri, '.yaml')));
+            (
+                (strpos($this->refPointer, self::REFERENCE_PATH) === 0) ||
+                (str_ends_with($this->uri, '.yml')) || (str_ends_with($this->uri, '.yaml')) || (str_ends_with($this->uri, '.json'))
+            );
     }
 
     public function isRefPointerToSelf():bool
@@ -310,7 +312,7 @@ public function getRefSchemaName():string
         $pattern = strpos($this->refPointer, '/properties/') !== false ?
             '~^'.self::REFERENCE_PATH.'(?<schemaName>.+)/properties/(?<propName>.+)$~'
             : '~^'.self::REFERENCE_PATH.'(?<schemaName>.+)$~';
-        $separateFilePattern = '/((\.\/)*)(?<schemaName>.+)(\.)(yml|yaml)(.*)/'; # https://github.com/php-openapi/yii2-openapi/issues/74
+        $separateFilePattern = '/((\.\/)*)(?<schemaName>.+)(\.)(yml|yaml|json)(.*)/'; # https://github.com/php-openapi/yii2-openapi/issues/74
         if (!\preg_match($pattern, $this->refPointer, $matches)) {
             if (!\preg_match($separateFilePattern, $this->uri, $separateFilePatternMatches)) {
                 throw new InvalidDefinitionException('Invalid schema reference');
diff --git a/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/Product.json b/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/Product.json
new file mode 100644
index 00000000..91514ab4
--- /dev/null
+++ b/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/Product.json
@@ -0,0 +1,22 @@
+{
+  "title": "Product",
+  "x-table": "products",
+  "type": "object",
+  "required": [
+    "id",
+    "vat_rate"
+  ],
+  "properties": {
+    "id": {
+      "type": "integer"
+    },
+    "vat_rate": {
+      "type": "string",
+      "enum": [
+        "standard",
+        "none"
+      ],
+      "default": "standard"
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.json b/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.json
new file mode 100644
index 00000000..a879d24c
--- /dev/null
+++ b/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.json
@@ -0,0 +1,39 @@
+{
+  "openapi": "3.0.0",
+  "info": {
+    "version": "1.0.0",
+    "title": "\\#87"
+  },
+  "paths": {
+    "/": {
+      "get": {
+        "responses": {
+          "200": {
+            "description": "The information"
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "Invoice": {
+        "type": "object",
+        "required": [
+          "vat_rate"
+        ],
+        "properties": {
+          "id": {
+            "type": "integer"
+          },
+          "vat_rate": {
+            "$ref": "./Product.json#/properties/vat_rate"
+          }
+        }
+      },
+      "Product": {
+        "$ref": "./Product.json"
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.php b/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.php
new file mode 100644
index 00000000..0fd4dc27
--- /dev/null
+++ b/tests/specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.php
@@ -0,0 +1,13 @@
+<?php
+
+return [
+    'openApiPath' => '@specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.json',
+    'generateUrls' => false,
+    'generateModels' => true,
+    'excludeModels' => [
+        'Error',
+    ],
+    'generateControllers' => false,
+    'generateMigrations' => true,
+    'generateModelFaker' => true,
+];
diff --git a/tests/unit/IssueFixTest.php b/tests/unit/IssueFixTest.php
index 9d20ae4d..08d1a00c 100644
--- a/tests/unit/IssueFixTest.php
+++ b/tests/unit/IssueFixTest.php
@@ -1029,4 +1029,19 @@ public function test23ConsiderOpenapiExtensionXNoRelationAlsoInOtherPertinentPla
         $this->checkFiles($actualFiles, $expectedFiles);
         $this->runActualMigrations();
     }
+
+    // https://github.com/php-openapi/yii2-openapi/issues/87
+    public function test87ImplementForJsonInIsrefpointertoschema()
+    {
+        $testFile = Yii::getAlias("@specs/issue_fix/87_implement_for_json_in_is_ref_pointer_to_schema/index.php");
+        $this->runGenerator($testFile);
+        $actualFiles = FileHelper::findFiles(Yii::getAlias('@app'), [
+            'recursive' => true,
+        ]);
+        $expectedFiles = FileHelper::findFiles(Yii::getAlias("@specs/issue_fix/74_invalid_schema_reference_error/mysql"), [ # this is intentional
+            'recursive' => true,
+        ]);
+        $this->checkFiles($actualFiles, $expectedFiles);
+        $this->runActualMigrations();
+    }
 }