diff --git a/kosynccloud.koplugin/_meta.lua b/kosynccloud.koplugin/_meta.lua
new file mode 100644
index 0000000..e0c2f5c
--- /dev/null
+++ b/kosynccloud.koplugin/_meta.lua
@@ -0,0 +1,6 @@
+local _ = require("gettext")
+return {
+    name = "kosynccloud",
+    fullname = _("Progress Cloudsync"),
+    description = _([[Synchronizes your reading progress across your KOReader devices.]]),
+}
diff --git a/kosynccloud.koplugin/main.lua b/kosynccloud.koplugin/main.lua
new file mode 100644
index 0000000..235605d
--- /dev/null
+++ b/kosynccloud.koplugin/main.lua
@@ -0,0 +1,366 @@
+local BD = require("ui/bidi")
+local ButtonDialog = require("ui/widget/buttondialog")
+local ConfirmBox = require("ui/widget/confirmbox")
+local DataStorage = require("datastorage")
+local Device = require("device")
+local Dispatcher = require("dispatcher")
+local Event = require("ui/event")
+local InfoMessage = require("ui/widget/infomessage")
+local Math = require("optmath")
+local MultiInputDialog = require("ui/widget/multiinputdialog")
+local NetworkMgr = require("ui/network/manager")
+local SQ3 = require("lua-ljsqlite3/init")
+local SyncService = require("frontend/apps/cloudstorage/syncservice")
+local UIManager = require("ui/uimanager")
+local WidgetContainer = require("ui/widget/container/widgetcontainer")
+local logger = require("logger")
+local md5 = require("ffi/sha2").md5
+local random = require("random")
+local time = require("ui/time")
+local util = require("util")
+local T = require("ffi/util").template
+local _ = require("gettext")
+
+-- Current DB schema version
+local DB_SCHEMA_VERSION = 20250120
+local db_location = DataStorage:getSettingsDir() .. "/kosynccloud.sqlite3"
+
+if G_reader_settings:hasNot("device_id") then
+    G_reader_settings:saveSetting("device_id", random.uuid())
+end
+
+local KOSyncCloud = WidgetContainer:extend {
+    name = "kosynccloud",
+    --is_doc = false,
+
+    last_page = nil,
+
+    is_enabled = nil,
+
+}
+
+KOSyncCloud.default_settings = {
+    is_enabled = true,
+}
+
+function KOSyncCloud:init()
+    self.last_page = -1
+    self.device_id = G_reader_settings:readSetting("device_id")
+
+    self.settings = G_reader_settings:readSetting("kosynccloud", self.default_settings)
+
+    self:checkInitDatabase()
+    self.ui.menu:registerToMainMenu(self)
+end
+
+function KOSyncCloud:addToMainMenu(menu_items)
+    menu_items.kosynccloud = {
+        text = _("Reading Progress Cloud"),
+        sorting_hint = "more_tools",
+        {
+            text = _("Cloud sync settings"),
+            callback = function(touchmenu_instance)
+                local server = self.settings.sync_server
+                local edit_cb = function()
+                    local sync_settings = SyncService:new {}
+                    sync_settings.onClose = function(this)
+                        UIManager:close(this)
+                    end
+                    sync_settings.onConfirm = function(sv)
+                        if server and (server.type ~= sv.type
+                                or server.url ~= sv.url
+                                or server.address ~= sv.address) then
+                            SyncService.removeLastSyncDB(db_location)
+                        end
+                        self.settings.sync_server = sv
+                        touchmenu_instance:updateItems()
+                    end
+                    UIManager:show(sync_settings)
+                end
+                if not server then
+                    edit_cb()
+                    return
+                end
+                local dialogue
+                local delete_button = {
+                    text = _("Delete"),
+                    callback = function()
+                        UIManager:close(dialogue)
+                        UIManager:show(ConfirmBox:new {
+                            text = _("Delete server info?"),
+                            cancel_text = _("Cancel"),
+                            cancel_callback = function()
+                                return
+                            end,
+                            ok_text = _("Delete"),
+                            ok_callback = function()
+                                self.settings.sync_server = nil
+                                SyncService.removeLastSyncDB(db_location)
+                                touchmenu_instance:updateItems()
+                            end,
+                        })
+                    end,
+                }
+                local edit_button = {
+                    text = _("Edit"),
+                    callback = function()
+                        UIManager:close(dialogue)
+                        edit_cb()
+                    end
+                }
+                local close_button = {
+                    text = _("Close"),
+                    callback = function()
+                        UIManager:close(dialogue)
+                    end
+                }
+                local type = server.type == "dropbox" and " (DropBox)" or " (WebDAV)"
+                dialogue = ButtonDialog:new {
+                    title = T(_("Cloud storage:\n%1\n\nFolder path:\n%2\n\nSet up the same cloud folder on each device to sync across your devices."),
+                        server.name .. " " .. type, SyncService.getReadablePath(server)),
+                    buttons = {
+                        { delete_button, edit_button, close_button }
+                    },
+                }
+                UIManager:show(dialogue)
+            end,
+            enabled_func = function() return self.settings.is_enabled end,
+            keep_menu_open = true,
+            separator = true,
+        },
+        {
+            text = _("Synchronize now"),
+            callback = function()
+                self:onSyncProgress()
+            end,
+            enabled_func = function()
+                return self:canSync()
+            end,
+            keep_menu_open = true,
+            separator = true,
+        },
+    }
+end
+
+function KOSyncCloud:canSync()
+    return self.settings.sync_server ~= nil and self.settings.is_enabled
+end
+
+function KOSyncCloud:checkInitDatabase()
+    local conn = SQ3.open(db_location)
+
+    if not conn:exec("PRAGMA table_info('progresses');") then
+        self:createDB(conn)
+    end
+
+    conn:close()
+end
+
+function KOSyncCloud:createDB(conn)
+    -- Make it WAL, if possible
+    if Device:canUseWAL() then
+        conn:exec("PRAGMA journal_mode=WAL;")
+    else
+        conn:exec("PRAGMA journal_mode=TRUNCATE;")
+    end
+
+    local sql_stmt = [[
+        CREATE TABLE IF NOT EXISTS progresses
+        (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            document TEXT UNIQUE,
+            progress TEXT,
+            percentage REAL,
+            device TEXT,
+            device_id TEXT,
+            timestamp INTEGER
+        );
+    ]]
+    conn:exec(sql_stmt)
+
+    -- DB schema version
+    conn:exec(string.format("PRAGMA user_version=%d;", DB_SCHEMA_VERSION))
+end
+
+function KOSyncCloud:getLastPercent()
+    if self.ui.document.info.has_pages then
+        return Math.roundPercent(self.ui.paging:getLastPercent())
+    else
+        return Math.roundPercent(self.ui.rolling:getLastPercent())
+    end
+end
+
+function KOSyncCloud:getLastProgress()
+    if self.ui.document.info.has_pages then
+        return self.ui.paging:getLastProgress()
+    else
+        return self.ui.rolling:getLastProgress()
+    end
+end
+
+function KOSyncCloud:getDocumentDigest()
+    return self.ui.doc_settings:readSetting("partial_md5_checksum")
+end
+
+function KOSyncCloud:getDocValuesFromDb()
+    local doc_digest = self:getDocumentDigest()
+
+    local conn = SQ3.open(db_location)
+
+    local stmt = conn:prepare("SELECT 1 FROM progresses WHERE document = ?;")
+    local result = stmt:reset():bind(doc_digest):step()
+
+    local progress, percentage, device_id = nil, nil, nil
+
+    if result ~= nil then
+        local sql_stmt = "SELECT progress, percentage, device_id FROM progresses WHERE document = '%s';"
+        progress, percentage, device_id = conn:rowexec(string.format(sql_stmt, doc_digest))
+    end
+
+    logger.dbg(progress, percentage, device_id)
+    conn:close()
+
+    return progress, percentage, device_id
+end
+
+function KOSyncCloud:showSyncedMessage()
+    UIManager:show(InfoMessage:new {
+        text = _("Progress has been synchronized."),
+        timeout = 3,
+    })
+end
+
+function KOSyncCloud:syncToProgress()
+    local progress, percentage, device_id = self:getDocValuesFromDb()
+    if device_id ~= nil and device_id ~= self.device_id then
+        if percentage ~= self:getLastPercent() then
+            logger.dbg("KOSyncCloud: [Sync] progress to", progress)
+            if self.ui.document.info.has_pages then
+                self.ui:handleEvent(Event:new("GotoPage", tonumber(progress)))
+            else
+                self.ui:handleEvent(Event:new("GotoXPointer", progress))
+            end
+            self:showSyncedMessage()
+        end
+    end
+end
+
+function KOSyncCloud:onReaderReady()
+    UIManager:nextTick(function()
+        self:syncToProgress()
+    end)
+
+    self:registerEvents()
+
+    self.last_page = self.ui:getCurrentPage()
+end
+
+function KOSyncCloud.onSync(local_path, cached_path, income_path)
+    -- TODO: Implement sync logic
+    local conn_income = SQ3.open(income_path)
+    local ok1, v1 = pcall(conn_income.rowexec, conn_income, "PRAGMA schema_version")
+    if not ok1 or tonumber(v1) == 0 then
+        -- no income db or wrong db, first time sync
+        logger.warn("Opening progress income DB failed", v1)
+        return true
+    end
+
+    local sql = "attach '" .. income_path:gsub("'", "''") .. "' as income_db;"
+
+    local conn_cached = SQ3.open(cached_path)
+    local ok2, v2 = pcall(conn_cached.rowexec, conn_cached, "PRAGMA schema_version")
+    local attached_cache
+    if not ok2 or tonumber(v2) == 0 then
+        -- no cached or error, no item to delete
+        logger.warn("Opening progress cached DB failed", v2)
+    else
+        attached_cache = true
+        sql = sql .. "attach '" .. cached_path:gsub("'", "''") .. [[' as cached_db;
+        ]]
+        -- Skip this part for now
+    end
+    conn_cached:close()
+    conn_income:close()
+
+    local conn = SQ3.open(local_path)
+    local ok3, v3 = pcall(conn.exec, conn, "PRAGMA schema_version")
+    if not ok3 or tonumber(v3) == 0 then
+        -- no local db, this is an error
+        logger.err("progress open local DB", v3)
+        return false
+    end
+
+    sql = sql .. [[
+        UPDATE progresses AS p
+          SET progress = i.progress,
+              percentage = i.percentage,
+              device = i.device,
+              device_id = i.device_id,
+              timestamp = i.timestamp
+          FROM income_db.progresses AS i
+          WHERE p.document = i.document AND p.timestamp < i.timestamp;
+
+        INSERT INTO progresses (
+            document, progress, percentage, device, device_id, timestamp
+          ) SELECT
+            document, progress, percentage, device, device_id, timestamp
+          FROM income_db.progresses
+          WHERE document NOT IN (SELECT document FROM progresses);
+    ]]
+
+    conn:exec(sql)
+    pcall(conn.exec, conn, "COMMIT;")
+    conn:exec("DETACH income_db;" .. (attached_cache and "DETACH cached_db;" or ""))
+    conn:close()
+
+    return true
+end
+
+function KOSyncCloud:onSyncProgress()
+    if not self:canSync() then return end
+
+    UIManager:show(InfoMessage:new {
+        text = _("Syncing reading progress. This may take a while."),
+        timeout = 1,
+    })
+
+    UIManager:nextTick(function()
+        SyncService.sync(self.settings.sync_server, db_location, self.onSync)
+    end)
+end
+
+function KOSyncCloud:registerEvents()
+    self.onPageUpdate = self._onPageUpdate
+end
+
+function KOSyncCloud:_onPageUpdate(page)
+    if page == nil then
+        return
+    end
+
+    if self.last_page ~= page then
+        self.last_page = page
+        self:updateProgress()
+    end
+end
+
+function KOSyncCloud:updateProgress()
+    local doc_digest = self:getDocumentDigest()
+    local progress = self:getLastProgress()
+    local percentage = self:getLastPercent()
+
+    local conn = SQ3.open(db_location)
+    local stmt = conn:prepare("SELECT 1 FROM progresses WHERE document = ?;")
+    local result = stmt:reset():bind(doc_digest):step()
+    if result == nil then
+        stmt = conn:prepare("INSERT INTO progresses VALUES (NULL, ?, ?, ?, ?, ?, (SELECT unixepoch()));")
+        stmt:reset():bind(doc_digest, progress, percentage, Device.model, self.device_id):step()
+    else
+        stmt = conn:prepare(
+            "UPDATE progresses SET progress = ?, percentage = ?, device = ?, device_id = ?, timestamp = (SELECT unixepoch()) WHERE document = ?;")
+        stmt:reset():bind(progress, percentage, Device.model, self.device_id, doc_digest):step()
+    end
+    conn:close()
+end
+
+return KOSyncCloud