diff --git a/lua/Trans/backend/baidu.lua b/lua/Trans/backend/baidu.lua
index 509fbf2..ab8d3bc 100644
--- a/lua/Trans/backend/baidu.lua
+++ b/lua/Trans/backend/baidu.lua
@@ -1,25 +1,20 @@
-local M     = {}
+local M = {
+    uri  = 'https://fanyi-api.baidu.com/api/trans/vip/translate',
+    salt = tostring(math.random(bit.lshift(1, 15))),
+}
 
 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)))
-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 tmp  = M.app_id .. data.str .. M.salt .. M.app_passwd
     local sign = Trans.util.md5.sumhexa(tmp)
 
     return {
         q     = data.str,
         from  = data.from,
         to    = data.to,
-        appid = app_id,
-        salt  = salt,
+        appid = M.app_id,
+        salt  = M.salt,
         sign  = sign,
     }
 end
@@ -33,7 +28,11 @@ end
 
 
 function M.query(data)
-    data.engine = 'baidu'
+    if M.disable then
+        data.result.baidu = false
+        return
+    end
+
 
     local handle = function(res)
         local status, body = pcall(vim.json.decode, res.body)
@@ -41,7 +40,7 @@ function M.query(data)
             local result = body.trans_result
             if result then
                 -- TEST :whether multi result
-                assert(#result == 1, 'multi result :' .. vim.inspect(result))
+                assert(#result == 1)
                 result = result[1]
                 data.result.baidu = {
                     title = result.src,
@@ -56,7 +55,7 @@ function M.query(data)
     end
 
 
-    Trans.wrapper.curl.get(uri, {
+    Trans.wrapper.curl.get(M.uri, {
         query = M.get_content(data),
         callback = handle,
     })
diff --git a/lua/Trans/backend/offline.lua b/lua/Trans/backend/offline.lua
index 36d6c60..4d39d76 100644
--- a/lua/Trans/backend/offline.lua
+++ b/lua/Trans/backend/offline.lua
@@ -1,4 +1,4 @@
-local M = { no_wait = true }
+local M = { no_wait = true, }
 
 local db = require 'sqlite.db'
 vim.api.nvim_create_autocmd('VimLeavePre', {
@@ -13,7 +13,6 @@ vim.api.nvim_create_autocmd('VimLeavePre', {
 function M.query(data)
     if data.is_word == false or data.from == 'zh' then return end
 
-
     data.path        = data.path or require('Trans').conf.dir .. '/ultimate.db'
     data.engine      = 'offline'
     data.formatter   = data.formatter or M.formatter
diff --git a/lua/Trans/core/backend.lua b/lua/Trans/core/backend.lua
new file mode 100644
index 0000000..21247b1
--- /dev/null
+++ b/lua/Trans/core/backend.lua
@@ -0,0 +1,32 @@
+local Trans = require('Trans')
+local M = Trans.metatable('backend')
+
+--- INFO :Parse online engine keys config file
+local path = Trans.conf.dir .. '/Trans.json'
+local file = io.open(path, "r")
+
+if file then
+    local content = file:read("*a")
+    local status, result = pcall(vim.json.decode, content)
+    file:close()
+    if not status then
+        error('Unable to parse json file: ' .. path .. '\n' .. result)
+    end
+
+
+
+    local default_opts = vim.deepcopy(Trans.conf.backend)
+    for name, private_opts in pairs(result or {}) do
+        local opts = vim.tbl_extend('keep', Trans.conf.backend[name] or {}, default_opts, private_opts)
+
+        local backend = M[name]
+        for k, v in pairs(opts) do
+            if not backend[k] then
+                backend[k] = v
+            end
+        end
+    end
+end
+
+
+return M
diff --git a/lua/Trans/core/setup.lua b/lua/Trans/core/setup.lua
index 5244200..011dafb 100644
--- a/lua/Trans/core/setup.lua
+++ b/lua/Trans/core/setup.lua
@@ -3,7 +3,7 @@ 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)
+    local all_backends = define.backends
 
     local function parse_backend(backend)
         if type(backend) == 'string' then
@@ -62,6 +62,26 @@ local function set_frontend_opts(conf)
 end
 
 
+local function define_keymaps(conf)
+    local set = vim.keymap.set
+    local opts = { silent = true, expr = true }
+
+
+    for _, name in ipairs(Trans.define.frontends) do
+        for action, key in pairs(conf.frontend[name].keymap) do
+            set('n', key, function()
+                local frontend = Trans.frontend[name]
+                if frontend.is_available() then
+                    frontend.actions[action]()
+                else
+                    return key
+                end
+            end, opts)
+        end
+    end
+end
+
+
 
 local function define_highlights(conf)
     local set_hl     = vim.api.nvim_set_hl
@@ -80,5 +100,6 @@ return function(opts)
 
     set_strategy_opts(conf)
     set_frontend_opts(conf)
+    define_keymaps(conf)
     define_highlights(conf)
 end
diff --git a/lua/Trans/core/translate.lua b/lua/Trans/core/translate.lua
index 14b7289..de1a09e 100644
--- a/lua/Trans/core/translate.lua
+++ b/lua/Trans/core/translate.lua
@@ -1,7 +1,6 @@
 local Trans = require('Trans')
 local util = Trans.util
 
-vim.pretty_print(Trans.conf)
 local function new_data(opts)
     opts = opts or {}
     local mode = opts.method or ({
@@ -28,37 +27,41 @@ local function new_data(opts)
         data.from = 'zh'
         data.to = 'en'
     end
+
+    -- TODO : Check if the str is a word
+    data.is_word = true
+
     return data
 end
 
 local function set_result(data)
-    -- local t_backend = require('Trans').backend
-    -- for _, name in rdata.backend do
-    --     local backend = t_backend[name]
-    --     backend.query(data)
-    --     if backend.no_wait then
+    local backend_list = data.backend
+    local backends = Trans.backend
 
-    --     end
-    -- end
 
-    -- Trans.backend.baidu.query(data)
-    -- local thread = coroutine.running()
-    -- local resume = function()
-    --     coroutine.resume(thread)
-    -- end
+    local frontend = Trans.frontend[data.frontend]
 
-    -- 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 function do_query(name)
+        local backend = backends[name]
+        if backend.no_wait then
+            backend.query(data)
+            if type(data.result[name]) == 'table' then
+                return
+            end
+        else
+            backend.query(data)
+            frontend.wait(data.result, name, backend.timeout)
+        end
+    end
+
+    for _, name in ipairs(backend_list) do
+        do_query(name)
+    end
 end
 
-local function render_window()
-
+local function render_window(data)
+    -- TODO
+    print('begin to render window')
 end
 
 -- HACK : Core process logic
@@ -71,7 +74,7 @@ local function process(opts)
     set_result(data)
     if data.result == false then return end
 
-    render_window()
+    render_window(data)
 end
 
 return coroutine.wrap(process)
diff --git a/lua/Trans/core/util.lua b/lua/Trans/core/util.lua
index 8397035..8e87543 100644
--- a/lua/Trans/core/util.lua
+++ b/lua/Trans/core/util.lua
@@ -36,18 +36,16 @@ end
 ---@param mode string 'n' | 'v' | 'i'
 ---@return string
 function M.get_str(mode)
-    return ({
-        normal = function()
-            return fn.expand('<cword>')
-        end,
-        visual = function()
-            api.nvim_input('<ESC>')
-            return M.get_select()
-        end,
-        input = function()
-            return fn.input('请输入需要查询的单词:')
-        end,
-    })[mode]()
+    if mode == 'n' or mode == 'normal' then
+        return fn.expand('<cword>')
+    elseif mode == 'v' or mode == 'visual' then
+        api.nvim_input('<ESC>')
+        return M.get_select()
+    elseif mode == 'input' then
+        return fn.expand('<cword>')
+    else
+        error('Unsupported mode' .. mode)
+    end
 end
 
 function M.is_English(str)
diff --git a/lua/Trans/frontend/hover.lua b/lua/Trans/frontend/hover.lua
index a95a71d..f59b702 100644
--- a/lua/Trans/frontend/hover.lua
+++ b/lua/Trans/frontend/hover.lua
@@ -1,16 +1,67 @@
 local M = {}
 
 local api = vim.api
+local conf = require('Trans').conf
 
-function M.process(data)
 
+function M.init()
+    print('TODO: init hover window')
 end
 
+function M.wait(tbl, key, timeout)
+    local thread = coroutine.running()
+    local function pause(ms)
+        vim.defer_fn(function()
+            coroutine.resume(thread)
+        end, ms)
+        coroutine.yield()
+    end
+
+    local error_message = 'Faild'
+    local times = 0
+    local interval = math.floor(timeout / #error_message)
+    while tbl[key] == nil do
+        print(('waitting' .. (' '):rep(times)))
+        pause(interval)
+    end
+
+    if tbl[key] == false then
+        print('TODO: show error message: ' .. error_message)
+    else
+        vim.pretty_print(tbl[key])
+    end
+end
+
+function M.process(data)
+    print('TODO: process data')
+end
+
+function M.is_available()
+    return true
+end
+
+M.actions = {
+    play = function()
+        print('TODO: play')
+    end,
+    pageup = function()
+        print('TODO: pageup')
+    end,
+    pagedown = function()
+        print('TODO: pagedown')
+    end,
+    pin = function()
+        print('TODO: pin')
+    end,
+    close = function()
+        print('TODO: close')
+    end,
+    toggle_entry = function()
+        print('TODO: toggle_entry')
+    end,
+}
 return M
 
-
--- local api = vim.api
--- local conf = require('Trans').conf
 -- local hover = conf.hover
 -- local error_msg = conf.icon.notfound .. '    没有找到相关的翻译'
 
diff --git a/lua/Trans/init.lua b/lua/Trans/init.lua
index 12b972a..13bb071 100644
--- a/lua/Trans/init.lua
+++ b/lua/Trans/init.lua
@@ -19,7 +19,6 @@ local M = metatable('core')
 M.metatable = metatable
 M.style     = metatable("style")
 M.wrapper   = metatable("wrapper")
-M.backend   = metatable("backend")
 M.frontend  = metatable("frontend")
 
 
diff --git a/lua/Trans/util/curl.lua b/lua/Trans/util/curl.lua
deleted file mode 100644
index c2d2c28..0000000
--- a/lua/Trans/util/curl.lua
+++ /dev/null
@@ -1,109 +0,0 @@
---- TODO :wrapper for curl
-local curl = {}
-
----Send a GET request
----@param opts table
-curl.GET = function(opts)
-    local uri = opts.uri
-    local headers = opts.headers or {}
-    local callback = opts.callback
-
-    -- INFO :Init Curl command with {s}ilent and {G}et
-    local cmd = { 'curl', '-Gs' }
-
-    -- INFO :Add headers
-    for k, v in pairs(headers) do
-        cmd[#cmd + 1] = ([[-H '%s: %s']]):format(k, v)
-    end
-
-    -- INFO :Add arguments
-    local info = {}
-    for k, v in pairs(opts.arguments) do
-        info[#info + 1] = ('%s=%s'):format(k, v)
-    end
-    cmd[#cmd + 1] = ([['%s?%s']]):format(uri, table.concat(info, '&'))
-
-
-    -- write a function to get the output
-    local outpus = {}
-    vim.fn.jobstart(table.concat(cmd, ' '), {
-        stdin = 'null',
-        on_stdout = function(_, stdout)
-            local str = table.concat(stdout)
-            if str ~= '' then
-
-            end
-        end,
-        on_exit = function()
-            callback(output)
-        end,
-    })
-
-    -- local output = ''
-    -- local option = {
-    --     stdin = 'null',
-    --     on_stdout = function(_, stdout)
-    --         local str = table.concat(stdout)
-    --         if str ~= '' then
-    --             output = output .. str
-    --         end
-    --     end,
-    --     on_exit = function()
-    --         callback(output)
-    --     end,
-    -- }
-
-    -- vim.fn.jobstart(table.concat(cmd, ' '), option)
-end
-
-
-
-curl.POST = function(opts)
-    vim.validate {
-        uri = { uri, 's' },
-        opts = { opts, 't' }
-    }
-
-    local callback = opts.callback
-
-    local cmd = { 'curl', '-s', ('"%s"'):format(uri) }
-    local size = 3
-
-    local function insert(...)
-        for _, v in ipairs { ... } do
-            size = size + 1
-            cmd[size] = v
-        end
-    end
-
-    local s = '"%s=%s"'
-
-    if opts.headers then
-        for k, v in pairs(opts.headers) do
-            insert('-H', s:format(k, v))
-        end
-    end
-
-    for k, v in pairs(opts.data) do
-        insert('-d', s:format(k, v))
-    end
-
-
-    local output = ''
-    local option = {
-        stdin = 'null',
-        on_stdout = function(_, stdout)
-            local str = table.concat(stdout)
-            if str ~= '' then
-                output = output .. str
-            end
-        end,
-        on_exit = function()
-            callback(output)
-        end,
-    }
-
-    vim.fn.jobstart(table.concat(cmd, ' '), option)
-end
-
-return curl
diff --git a/plugin/Trans.lua b/plugin/Trans.lua
index 4a57fc7..6b53b76 100644
--- a/plugin/Trans.lua
+++ b/plugin/Trans.lua
@@ -31,32 +31,3 @@ command('TransPlay', function()
         str:play()
     end
 end, { desc = ' 自动发音' })
-
-
-
---- 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")
-
-    if file then
-        local content = file:read("*a")
-        local status, result = pcall(vim.json.decode, content)
-        file:close()
-        assert(status, 'Unable to parse json file: ' .. path)
-        return result
-    end
-end
-
-local result = parse_engine_file()
-if result then
-    for name, opts in pairs(result) do
-        if not opts.enable then
-            result[name] = nil
-        end
-    end
-
-    Trans.conf.keys = result
-else
-    Trans.conf.keys = {}
-end