diff --git a/lua/Trans/backend/baidu.lua b/lua/Trans/backend/baidu.lua
index 568d77a..509fbf2 100644
--- a/lua/Trans/backend/baidu.lua
+++ b/lua/Trans/backend/baidu.lua
@@ -1,6 +1,9 @@
-local M = {}
+local M     = {}
 
-local baidu      = require('Trans').conf.engines.baidu
+local Trans = require('Trans')
+
+
+local baidu      = Trans.conf.keys.baidu
 local app_id     = baidu.app_id
 local app_passwd = baidu.app_passwd
 local salt       = tostring(math.random(bit.lshift(1, 15)))
@@ -9,7 +12,8 @@ local uri        = 'https://fanyi-api.baidu.com/api/trans/vip/translate'
 
 function M.get_content(data)
     local tmp  = app_id .. data.str .. salt .. app_passwd
-    local sign = require('Trans.util.md5').sumhexa(tmp)
+    local sign = Trans.util.md5.sumhexa(tmp)
+
     return {
         q     = data.str,
         from  = data.from,
@@ -51,7 +55,8 @@ function M.query(data)
         data.trace = res
     end
 
-    require('Trans.wrapper.curl').get(uri, {
+
+    Trans.wrapper.curl.get(uri, {
         query = M.get_content(data),
         callback = handle,
     })
diff --git a/lua/Trans/backend/init.lua b/lua/Trans/backend/init.lua
deleted file mode 100644
index 4ede63a..0000000
--- a/lua/Trans/backend/init.lua
+++ /dev/null
@@ -1,10 +0,0 @@
-return setmetatable({}, {
-    __index = function(t, k)
-        local res, engine = pcall(require, [[Trans.backend.]] .. k)
-        if not res then
-            error([[Fail to load backend: ]] .. k .. '\n  ' .. engine)
-        end
-        t[k] = engine
-        return engine
-    end
-})
diff --git a/lua/Trans/core/conf.lua b/lua/Trans/core/conf.lua
index a8dc3da..983fe13 100644
--- a/lua/Trans/core/conf.lua
+++ b/lua/Trans/core/conf.lua
@@ -8,7 +8,7 @@ if vim.fn.has('nvim-0.9') == 1 then
 end
 
 return {
-    dir      = '$HOME/.vim/dict',
+    dir      = os.getenv('HOME') .. '/.vim/dict',
     strategy = {
         frontend = 'hover',
         backend = '*',
@@ -24,7 +24,7 @@ return {
             close = 'slid',
             interval = 12,
         },
-        title = title,     -- need nvim-0.9
+        title = title, -- need nvim-0.9
         hover = {
             width = 37,
             height = 27,
diff --git a/lua/Trans/core/install.lua b/lua/Trans/core/install.lua
index a9ede8e..211cdbe 100644
--- a/lua/Trans/core/install.lua
+++ b/lua/Trans/core/install.lua
@@ -1,7 +1,9 @@
 return function()
+    local Trans = require('Trans')
     -- INFO :Check ultimate.db exists
-    local dir = require('Trans').conf.dir
+    local dir = Trans.conf.dir
     local path = dir .. '/ultimate.db'
+
     if vim.fn.filereadable(path) == 1 then
         vim.notify('Database already exists', vim.log.WARN)
         return
@@ -33,7 +35,8 @@ return function()
         vim.notify(debug_message, vim.log.ERROR)
     end
 
-    require('Trans.wrapper.curl').get(uri, {
+
+    Trans.wrapper.curl.get(uri, {
         output = loc,
         callback = handle,
     })
diff --git a/lua/Trans/core/setup.lua b/lua/Trans/core/setup.lua
index 1a00684..5244200 100644
--- a/lua/Trans/core/setup.lua
+++ b/lua/Trans/core/setup.lua
@@ -1,9 +1,10 @@
-local function set_strategy_opts(conf)
-    local define       = require('Trans').define
-    local all_modes    = define.modes
-    local all_backends = vim.tbl_keys(conf.engines)
+local Trans = require('Trans')
+
+local function set_strategy_opts(conf)
+    local define       = Trans.define
+    local all_modes    = define.modes
+    local all_backends = vim.tbl_keys(conf.keys)
 
-    -- FIXME : Wrong backend baidu
     local function parse_backend(backend)
         if type(backend) == 'string' then
             return backend == '*' and all_backends or { backend }
@@ -11,6 +12,7 @@ local function set_strategy_opts(conf)
 
         return backend
     end
+
     local global_strategy = conf.strategy
     global_strategy.backend = parse_backend(global_strategy.backend)
 
@@ -38,7 +40,7 @@ end
 
 
 local function set_frontend_opts(conf)
-    local all_frontends = require('Trans').define.frontends
+    local all_frontends = Trans.define.frontends
 
 
     local global_frontend_opts = conf.frontend
@@ -63,18 +65,17 @@ end
 
 local function define_highlights(conf)
     local set_hl     = vim.api.nvim_set_hl
-    local highlights = require('Trans.style.theme')[conf.style.theme]
+    local highlights = Trans.style.theme[conf.style.theme]
     for hl, opt in pairs(highlights) do
         set_hl(0, hl, opt)
     end
 end
 
 return function(opts)
-    local M = require('Trans')
     if opts then
-        M.conf = vim.tbl_deep_extend('force', M.conf, opts)
+        Trans.conf = vim.tbl_deep_extend('force', Trans.conf, opts)
     end
-    local conf = M.conf
+    local conf = Trans.conf
     conf.dir = vim.fn.expand(conf.dir)
 
     set_strategy_opts(conf)
diff --git a/lua/Trans/core/translate.lua b/lua/Trans/core/translate.lua
index 66c505b..14b7289 100644
--- a/lua/Trans/core/translate.lua
+++ b/lua/Trans/core/translate.lua
@@ -32,7 +32,7 @@ local function new_data(opts)
 end
 
 local function set_result(data)
-    -- local t_backend = require('Trans.backend')
+    -- local t_backend = require('Trans').backend
     -- for _, name in rdata.backend do
     --     local backend = t_backend[name]
     --     backend.query(data)
@@ -41,20 +41,20 @@ local function set_result(data)
     --     end
     -- end
 
-    require('Trans.backend').baidu.query(data)
-    local thread = coroutine.running()
-    local resume = function()
-        coroutine.resume(thread)
-    end
+    -- Trans.backend.baidu.query(data)
+    -- local thread = coroutine.running()
+    -- local resume = function()
+    --     coroutine.resume(thread)
+    -- end
 
-    local time = 0
-    while data.result == nil do
-        vim.defer_fn(resume, 400)
-        time = time + 1
-        print('waiting' .. ('.'):rep(time))
-        coroutine.yield()
-    end
-    vim.pretty_print(data)
+    -- local time = 0
+    -- while data.result == nil do
+    --     vim.defer_fn(resume, 400)
+    --     time = time + 1
+    --     print('waiting' .. ('.'):rep(time))
+    --     coroutine.yield()
+    -- end
+    -- vim.pretty_print(data)
 end
 
 local function render_window()
diff --git a/lua/Trans/core/util.lua b/lua/Trans/core/util.lua
index 00626f5..8397035 100644
--- a/lua/Trans/core/util.lua
+++ b/lua/Trans/core/util.lua
@@ -1,4 +1,5 @@
-local M = {}
+M = require('Trans').metatable('util')
+
 local fn, api = vim.fn, vim.api
 
 function M.get_select()
diff --git a/lua/Trans/init.lua b/lua/Trans/init.lua
index ac3a72b..12b972a 100644
--- a/lua/Trans/init.lua
+++ b/lua/Trans/init.lua
@@ -1,13 +1,27 @@
-local M = setmetatable({}, {
-    __index = function(tbl, key)
-        local status, field = pcall(require, 'Trans.core.' .. key)
-        assert(status, 'Unknown field: ' .. key)
-        
-        tbl[key] = field
-        return field
-    end
-})
+local function metatable(folder_name)
+    return setmetatable({}, {
+        __index = function(tbl, key)
+            local status, result = pcall(require, ('Trans.%s.%s'):format(folder_name, key))
+
+            if not status then
+                error('fail to load: ' .. key .. '\n' .. result)
+            end
+
+            tbl[key] = result
+            return result
+        end
+    })
+end
+
+local M = metatable('core')
+
+
+M.metatable = metatable
+M.style     = metatable("style")
+M.wrapper   = metatable("wrapper")
+M.backend   = metatable("backend")
+M.frontend  = metatable("frontend")
+
 
 M.cache = {}
-
 return M
diff --git a/lua/Trans/util/json.lua b/lua/Trans/util/json.lua
deleted file mode 100644
index 94f743a..0000000
--- a/lua/Trans/util/json.lua
+++ /dev/null
@@ -1,12 +0,0 @@
-local function read_json()
-  local path = vim.fn.expand("$HOME/.config/Trans.json")
-  local file = io.open(path, "r")
-  if file then
-    local content = file:read("*a")
-    file:close()
-    local data = vim.json.decode(content)
-    print(data.api_key, data.api_id)
-  else
-    print("File not found: " .. path)
-  end
-end
diff --git a/plugin/Trans.lua b/plugin/Trans.lua
index 779e835..4a57fc7 100644
--- a/plugin/Trans.lua
+++ b/plugin/Trans.lua
@@ -34,7 +34,7 @@ end, { desc = ' 自动发音' })
 
 
 
---- INFO :Parse online engines config file
+--- INFO :Parse online engine keys config file
 local function parse_engine_file()
     local path = Trans.conf.dir .. '/Trans.json'
     local file = io.open(path, "r")
@@ -55,8 +55,8 @@ if result then
             result[name] = nil
         end
     end
-    Trans.conf.engines = result
 
+    Trans.conf.keys = result
 else
-    Trans.conf.engines = {}
+    Trans.conf.keys = {}
 end