diff --git a/frontend/ui/widget/container/inputcontainer.lua b/frontend/ui/widget/container/inputcontainer.lua
index 95aa9727d..bde01dd09 100644
--- a/frontend/ui/widget/container/inputcontainer.lua
+++ b/frontend/ui/widget/container/inputcontainer.lua
@@ -99,6 +99,7 @@ function InputContainer:onInput(input)
     local InputDialog = require("ui/widget/inputdialog")
     self.input_dialog = InputDialog:new{
         title = input.title or "",
+        input = input.input,
         input_hint = input.hint_func and input.hint_func() or input.hint or "",
         input_type = input.type or "number",
         buttons = {
diff --git a/plugins/kosync.koplugin/KOSyncClient.lua b/plugins/kosync.koplugin/KOSyncClient.lua
index 1789e7ae0..5b6afc93d 100644
--- a/plugins/kosync.koplugin/KOSyncClient.lua
+++ b/plugins/kosync.koplugin/KOSyncClient.lua
@@ -3,6 +3,7 @@ local DEBUG = require("dbg")
 
 local KOSyncClient = {
     service_spec = nil,
+    custom_url = nil,
 }
 
 function KOSyncClient:new(o)
@@ -15,7 +16,9 @@ end
 
 function KOSyncClient:init()
     local Spore = require("Spore")
-    self.client = Spore.new_from_spec(self.service_spec)
+    self.client = Spore.new_from_spec(self.service_spec, {
+        base_url = self.custom_url,
+    })
     package.loaded['Spore.Middleware.GinClient'] = {}
     require('Spore.Middleware.GinClient').call = function(self, req)
         req.headers['accept'] = "application/vnd.koreader.v1+json"
diff --git a/plugins/kosync.koplugin/main.lua b/plugins/kosync.koplugin/main.lua
index 8d40f051d..0d6093e92 100644
--- a/plugins/kosync.koplugin/main.lua
+++ b/plugins/kosync.koplugin/main.lua
@@ -27,6 +27,7 @@ local KOSync = InputContainer:new{
 
 function KOSync:init()
     local settings = G_reader_settings:readSetting("kosync") or {}
+    self.kosync_custom_server = settings.custom_server
     self.kosync_username = settings.username
     self.kosync_userkey = settings.userkey
     self.kosync_auto_sync = not (settings.auto_sync == false)
@@ -69,11 +70,28 @@ function KOSync:addToMainMenu(tab_item_table)
                     self:updateProgress()
                     self:getProgress(true)
                 end,
-            }
+            },
+            {
+                text = _("Custom sync server"),
+                tap_input = {
+                    title = _("Custom progress sync server address"),
+                    input = self.kosync_custom_server or "https://",
+                    type = "text",
+                    callback = function(input)
+                        self:setCustomServer(input)
+                    end,
+                },
+            },
         }
     })
 end
 
+function KOSync:setCustomServer(server)
+    DEBUG("set custom server", server)
+    self.kosync_custom_server = server ~= "" and server or nil
+    self:onSaveSettings()
+end
+
 function KOSync:login()
     if NetworkMgr:getWifiStatus() == false then
         NetworkMgr:promptWifiOn()
@@ -144,6 +162,7 @@ end
 function KOSync:doRegister(username, password)
     local KOSyncClient = require("KOSyncClient")
     local client = KOSyncClient:new{
+        custom_url = self.kosync_custom_server,
         service_spec = self.path .. "/api.json"
     }
     local userkey = md5:sum(password)
@@ -173,6 +192,7 @@ end
 function KOSync:doLogin(username, password)
     local KOSyncClient = require("KOSyncClient")
     local client = KOSyncClient:new{
+        custom_url = self.kosync_custom_server,
         service_spec = self.path .. "/api.json"
     }
     local userkey = md5:sum(password)
@@ -234,6 +254,7 @@ function KOSync:updateProgress()
     if self.kosync_username and self.kosync_userkey then
         local KOSyncClient = require("KOSyncClient")
         local client = KOSyncClient:new{
+            custom_url = self.kosync_custom_server,
             service_spec = self.path .. "/api.json"
         }
         local doc_digest = self.view.document:fastDigest()
@@ -255,6 +276,7 @@ function KOSync:getProgress(manual)
     if self.kosync_username and self.kosync_userkey then
         local KOSyncClient = require("KOSyncClient")
         local client = KOSyncClient:new{
+            custom_url = self.kosync_custom_server,
             service_spec = self.path .. "/api.json"
         }
         local doc_digest = self.view.document:fastDigest()
@@ -291,6 +313,7 @@ end
 
 function KOSync:onSaveSettings()
     local settings = {
+        custom_server = self.kosync_custom_server,
         username = self.kosync_username,
         userkey = self.kosync_userkey,
         auto_sync = self.kosync_auto_sync,