diff --git a/src/backend/src/routers/filesystem_api/readdir-subdomains.js b/src/backend/src/routers/filesystem_api/readdir-subdomains.js
new file mode 100644
index 000000000..f336df1b3
--- /dev/null
+++ b/src/backend/src/routers/filesystem_api/readdir-subdomains.js
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2026-present Puter Technologies Inc.
+ *
+ * This file is part of Puter.
+ *
+ * Puter is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+'use strict';
+const { Context } = require('../../util/context.js');
+const eggspress = require('../../api/eggspress.js');
+const { DB_READ } = require('../../services/database/consts');
+const config = require('../../config');
+
+// -----------------------------------------------------------------------//
+// POST /readdir-subdomains
+// -----------------------------------------------------------------------//
+module.exports = eggspress('/readdir-subdomains', {
+    subdomain: 'api',
+    auth2: true,
+    verified: true,
+    json: true,
+    allowedMethods: ['POST'],
+}, async (req, res, next) => {
+    let log; {
+        const x = Context.get();
+        log = x.get('services').get('log-service').create('readdir-subdomains', {
+            concern: 'filesystem',
+        });
+        log.debug('readdir-subdomains: batch fetch subdomains');
+    }
+
+    const { directory_ids } = req.body;
+
+    if ( !Array.isArray(directory_ids) || directory_ids.length === 0 ) {
+        return res.status(400).send({
+            code: 'invalid_request',
+            message: 'directory_ids must be a non-empty array',
+        });
+    }
+
+    const user = req.user;
+    const db = Context.get().get('services').get('database').get(DB_READ, 'filesystem');
+
+    // Note: directory_ids are actually UUIDs (not database IDs) because fsentry.id is set to uuid in getSafeEntry()
+    // We need to convert UUIDs to database IDs first
+    log.debug(`readdir-subdomains: received ${directory_ids.length} directory UUIDs:`, directory_ids);
+
+    // Convert UUIDs to database IDs
+    const uuidPlaceholders = directory_ids.map(() => '?').join(',');
+    const fsentries = await db.read(`SELECT id, uuid FROM fsentries WHERE uuid IN (${uuidPlaceholders})`,
+                    directory_ids);
+
+    // Create maps: uuid -> db_id and db_id -> uuid
+    const uuidToDbId = new Map();
+    const dbIdToUuid = new Map();
+    for ( const fsentry of fsentries ) {
+        uuidToDbId.set(fsentry.uuid, fsentry.id);
+        dbIdToUuid.set(fsentry.id, fsentry.uuid);
+    }
+
+    const dbIds = Array.from(uuidToDbId.values());
+    log.debug(`readdir-subdomains: converted to ${dbIds.length} database IDs:`, dbIds);
+    log.debug(`readdir-subdomains: user_id: ${user.id}`);
+
+    if ( dbIds.length === 0 ) {
+        return res.send(directory_ids.map(dirUuid => ({
+            directory_id: dirUuid,
+            subdomains: [],
+            has_website: false,
+        })));
+    }
+
+    // Build the query with placeholders using database IDs
+    const placeholders = dbIds.map(() => '?').join(',');
+    const rows = await db.read(`SELECT root_dir_id, subdomain, uuid
+         FROM subdomains
+         WHERE root_dir_id IN (${placeholders}) AND user_id = ?`,
+    [...dbIds, user.id]);
+
+    log.debug(`readdir-subdomains: found ${rows.length} subdomain rows`);
+
+    // Group subdomains by database ID
+    const subdomainsByDbId = {};
+
+    for ( const row of rows ) {
+        if ( ! subdomainsByDbId[row.root_dir_id] ) {
+            subdomainsByDbId[row.root_dir_id] = [];
+        }
+        subdomainsByDbId[row.root_dir_id].push({
+            subdomain: row.subdomain,
+            address: `${config.protocol}://${row.subdomain}.puter.site`,
+            uuid: row.uuid,
+        });
+    }
+
+    // Build response: array of { directory_id, subdomains, has_website }
+    // Map back to original UUIDs (directory_ids)
+    const result = directory_ids.map(dirUuid => {
+        const dbId = uuidToDbId.get(dirUuid);
+        const subdomains = dbId ? (subdomainsByDbId[dbId] || []) : [];
+        const has_website = subdomains.length > 0;
+
+        log.debug(`readdir-subdomains: directory_id ${dirUuid} (db_id: ${dbId}) -> ${subdomains.length} subdomains, has_website: ${has_website}`);
+
+        return {
+            directory_id: dirUuid,
+            subdomains: subdomains,
+            has_website: has_website,
+        };
+    });
+
+    log.debug(`readdir-subdomains: returning ${result.length} results`);
+    res.send(result);
+    return;
+});