diff --git a/localtests/lowercase.js b/localtests/lowercase.js
new file mode 100644
index 00000000..14fe1a41
--- /dev/null
+++ b/localtests/lowercase.js
@@ -0,0 +1,32 @@
+const fs = require('fs');
+const path = require('path');
+
+const domainsDir = path.join(__dirname, '../domains');
+
+function lowercaseFilenames() {
+    fs.readdir(domainsDir, (err, files) => {
+        if (err) {
+            console.error(`Error reading directory: ${err.message}`);
+            return;
+        }
+
+        files.forEach(file => {
+            const currentPath = path.join(domainsDir, file);
+            const lowerCaseFile = file.toLowerCase();
+            const lowerCasePath = path.join(domainsDir, lowerCaseFile);
+
+            if (file !== lowerCaseFile) {
+                fs.rename(currentPath, lowerCasePath, err => {
+                    if (err) {
+                        console.error(`Error renaming file ${file}: ${err.message}`);
+                    } else {
+                        console.log(`Renamed: ${file} → ${lowerCaseFile}`);
+                    }
+                });
+            }
+        });
+    });
+}
+
+// Run the renamer
+lowercaseFilenames();
diff --git a/localtests/test.js b/localtests/test.js
index 87c1b8e2..52165650 100644
--- a/localtests/test.js
+++ b/localtests/test.js
@@ -13,7 +13,8 @@ const sectionMap = {
     1: 'Non-JSON file detection',
     2: 'JSON syntax validation',
     3: 'Owner property validation',
-    4: 'Filename format validation'
+    4: 'Filename format validation',
+    5: 'Filename content match validation'
 };
 
 function askQuestion(query) {
@@ -182,4 +183,38 @@ function askQuestion(query) {
                 });
         });
     }
+
+    //==================== SECTION 5: FILENAME CONTENT MATCH VALIDATION ====================//
+    if (selectedSections.includes(5)) {
+        fs.readdir(domainsDir, (err, files) => {
+            if (err) {
+                console.error(`Error reading directory: ${err.message}`);
+                return;
+            }
+
+            files
+                .filter(file => file.endsWith('.json'))
+                .forEach(file => {
+                    const filePath = path.join(domainsDir, file);
+                    fs.readFile(filePath, 'utf8', (err, data) => {
+                        if (err) {
+                            console.error(`Error reading file ${file}: ${err.message}`);
+                            return;
+                        }
+
+                        try {
+                            const parsed = JSON.parse(data);
+                            const expectedFileName = `${parsed.subdomain}.${parsed.domain}.json`;
+
+                            if (file !== expectedFileName) {
+                                console.warn(`❌ Filename mismatch in: ${file}`);
+                                console.warn(`   ↪ Expected: ${expectedFileName}`);
+                            }
+                        } catch (e) {
+                            console.log(`❌ Cannot parse JSON in: ${file}`);
+                        }
+                    });
+                });
+        });
+    }
 })();
\ No newline at end of file
diff --git a/package.json b/package.json
index d7e38992..53fabf10 100644
--- a/package.json
+++ b/package.json
@@ -6,6 +6,7 @@
   "scripts": {
     "test": "npx ava tests/*.test.js",
     "lt": "node ./localtests/test.js",
-    "format": "node ./localtests/format.js"
+    "format": "node ./localtests/format.js",
+    "lowercase": "node ./localtests/lowercase.js"
   }
 }