diff --git a/lib/config.js b/lib/config.js
index 4665bcb..d4f4581 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -49,7 +49,7 @@ class Config {
 function applyDefaults(cfg = {}, defaults = {}) {
   for (const d in defaults) {
     /* c8 ignore next */
-    if (d === "__proto__" || d === "constructor") continue;
+    if (d === '__proto__' || d === 'constructor') continue
     if ([undefined, null].includes(cfg[d])) {
       cfg[d] = defaults[d]
     } else if (typeof cfg[d] === 'object' && typeof defaults[d] === 'object') {
diff --git a/lib/permission.js b/lib/permission.js
index ff9729d..3235da6 100644
--- a/lib/permission.js
+++ b/lib/permission.js
@@ -39,7 +39,9 @@ class Permission {
     const rows = await Mysql.select(query, mapToDbColumn(args, permDbMap))
     if (rows.length === 0) return
     if (rows.length > 1) {
-      throw new Error(`permissions.get found ${rows.length} rows for uid ${args.uid}`)
+      throw new Error(
+        `permissions.get found ${rows.length} rows for uid ${args.uid}`,
+      )
     }
     return dbToObject(rows[0])
   }
@@ -56,8 +58,8 @@ class Permission {
     INNER JOIN nt_user u ON p.nt_group_id = u.nt_group_id
     WHERE p.deleted=0
       AND u.deleted=0
-      AND u.nt_user_id=?`;
-    const rows = await Mysql.select(query, [ args.uid ])
+      AND u.nt_user_id=?`
+    const rows = await Mysql.select(query, [args.uid])
     return dbToObject(rows[0])
   }
 
@@ -166,10 +168,9 @@ JSON object format:
   "inherit": true,
   "name": "Test Permission",
   "self_write": false,
-  "usable_ns": "",
   "deleted": false,
   "group": { "id": 4096, "create": false, "write": false, "delete": false },
-  "nameserver": { "create": false, "write": false, "delete": false },
+  "nameserver": { "usable": [], "create": false, "write": false, "delete": false },
   "zone": { "create": true, "write": true, "delete": true, "delegate": true },
   "zonerecord": {
     "create": false,
@@ -181,16 +182,12 @@ JSON object format:
 }
 */
 
-const boolFields = [
-  'self_write',
-  'inherit',
-  'deleted',
-]
+const boolFields = ['self_write', 'inherit', 'deleted']
 
 function dbToObject(row) {
   const newRow = JSON.parse(JSON.stringify(row))
   for (const f of ['group', 'nameserver', 'zone', 'zonerecord', 'user']) {
-    for (const p of ['create','write','delete','delegate']) {
+    for (const p of ['create', 'write', 'delete', 'delegate']) {
       if (newRow[`${f}_${p}`] !== undefined) {
         if (newRow[f] === undefined) newRow[f] = {}
         newRow[f][p] = newRow[`${f}_${p}`] === 1
@@ -209,10 +206,15 @@ function dbToObject(row) {
     newRow.group.id = newRow.gid
     delete newRow.gid
   }
+  newRow.nameserver.usable = []
+  if (![undefined, ''].includes(newRow.usable_ns)) {
+    newRow.nameserver.usable = newRow.usable_ns.split(',')
+  }
+  delete newRow.usable_ns
   return newRow
 }
 
-function objectToDb (row) {
+function objectToDb(row) {
   const newRow = JSON.parse(JSON.stringify(row))
   if (newRow?.user?.id !== undefined) {
     newRow.uid = newRow.user.id
@@ -222,8 +224,12 @@ function objectToDb (row) {
     newRow.gid = newRow.group.id
     delete newRow.group.id
   }
+  if (newRow?.nameserver?.usable !== undefined) {
+    newRow.usable_ns = newRow.nameserver.usable.join(',')
+    delete newRow.nameserver.usable
+  }
   for (const f of ['group', 'nameserver', 'zone', 'zonerecord', 'user']) {
-    for (const p of ['create','write','delete','delegate']) {
+    for (const p of ['create', 'write', 'delete', 'delegate']) {
       if (newRow[f] === undefined) continue
       if (newRow[f][p] === undefined) continue
       newRow[`${f}_${p}`] = newRow[f][p] === true ? 1 : 0
diff --git a/lib/permission.test.js b/lib/permission.test.js
index 3d4186b..9cdc163 100644
--- a/lib/permission.test.js
+++ b/lib/permission.test.js
@@ -20,19 +20,31 @@ describe('permission', function () {
   })
 
   it('get: by id', async () => {
-    assert.deepEqual(await Permission.get({ id: permTestCase.id }), permTestCase)
+    assert.deepEqual(
+      await Permission.get({ id: permTestCase.id }),
+      permTestCase,
+    )
   })
 
   it('get: by user id', async () => {
-    assert.deepEqual(await Permission.get({ uid: permTestCase.user.id }), permTestCase)
+    assert.deepEqual(
+      await Permission.get({ uid: permTestCase.user.id }),
+      permTestCase,
+    )
   })
 
   it('get: by group id', async () => {
-    assert.deepEqual(await Permission.get({ gid: permTestCase.group.id }), permTestCase)
+    assert.deepEqual(
+      await Permission.get({ gid: permTestCase.group.id }),
+      permTestCase,
+    )
   })
 
   it('getGroup: gets group permissions', async () => {
-    assert.deepEqual(await Permission.getGroup({ uid: permTestCase.user.id }), permTestCase)
+    assert.deepEqual(
+      await Permission.getGroup({ uid: permTestCase.user.id }),
+      permTestCase,
+    )
   })
 
   it('changes a permission', async () => {
diff --git a/lib/test/permission.json b/lib/test/permission.json
index 6267b91..21b10b3 100644
--- a/lib/test/permission.json
+++ b/lib/test/permission.json
@@ -3,10 +3,14 @@
   "inherit": true,
   "name": "Test Permission",
   "self_write": false,
-  "usable_ns": "",
   "deleted": false,
   "group": { "id": 4096, "create": false, "write": false, "delete": false },
-  "nameserver": { "create": false, "write": false, "delete": false },
+  "nameserver": {
+    "usable": [],
+    "create": false,
+    "write": false,
+    "delete": false
+  },
   "zone": { "create": true, "write": true, "delete": true, "delegate": true },
   "zonerecord": {
     "create": false,
@@ -15,4 +19,4 @@
     "delegate": false
   },
   "user": { "id": 4096, "create": false, "write": false, "delete": false }
-}
\ No newline at end of file
+}