diff --git a/.vimrc b/.vimrc
index 967bee9..c7ac21f 100644
--- a/.vimrc
+++ b/.vimrc
@@ -14,7 +14,6 @@ Plug 'prabirshrestha/asyncomplete-tscompletejob.vim'
 Plug 'tomasr/molokai'
 Plug 'scrooloose/nerdcommenter'
 Plug 'vim-scripts/DrawIt'
-Plug 'scrooloose/nerdtree'
 Plug 'easymotion/vim-easymotion'
 Plug 'mattn/emmet-vim'
 Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }
@@ -32,6 +31,13 @@ Plug 'godlygeek/tabular'
 Plug 'plasticboy/vim-markdown'
 Plug 'ctrlpvim/ctrlp.vim'
 
+" defx file explorer
+" require python package pynvim
+" install `pip3 install --user pynvim`
+Plug 'Shougo/defx.nvim'
+Plug 'roxma/nvim-yarp'
+Plug 'roxma/vim-hug-neovim-rpc'
+
 " LSP
 " JS/TS require
 " npm install -g typescript typescript-language-server
@@ -109,17 +115,83 @@ nmap <leader>swd <c-w>l
 nmap <leader>aa gT
 nmap <leader>dd gt
 
-" nerdtree key map
-nmap <F3> :NERDTreeToggle<CR>
-nmap <leader>me :NERDTreeToggle<CR>
-" show hidden file
-let NERDTreeShowHidden=1
-" delete auto remove buffer
-let NERDTreeAutoDeleteBuffer=1
+" defx settings
+call defx#custom#option('_', {
+  \ 'winwidth': 40,
+  \ 'split': 'vertical',
+  \ 'direction': 'topleft',
+  \ 'buffer_name': '',
+  \ 'toggle': 1,
+  \ 'resume': 1
+  \ })
+nmap <F3> :Defx<CR>
+nmap <leader>me :Defx<CR>
+autocmd FileType defx call s:defx_my_settings()
+function! s:defx_my_settings() abort
+  " Define mappings
+  nnoremap <silent><buffer><expr> <CR>
+  \ defx#is_directory() ?
+  \ defx#do_action('open_tree', 'toggle') :
+  \ defx#do_action('drop')
+  nnoremap <silent><buffer><expr> T
+  \ defx#do_action('open', 'tabe')
+  nnoremap <silent><buffer><expr> s
+  \ defx#do_action('drop', 'vsplit')
+  nnoremap <silent><buffer><expr> mc
+  \ defx#do_action('copy')
+  nnoremap <silent><buffer><expr> mm
+  \ defx#do_action('move')
+  nnoremap <silent><buffer><expr> mp
+  \ defx#do_action('paste')
+  nnoremap <silent><buffer><expr> P
+  \ defx#do_action('preview')
+  nnoremap <silent><buffer><expr> o
+  \ defx#do_action('open_tree', 'toggle')
+  nnoremap <silent><buffer><expr> ma
+  \ defx#do_action('new_file')
+  nnoremap <silent><buffer><expr> C
+  \ defx#do_action('toggle_columns',
+  \                'mark:indent:icon:filename:type:size:time')
+  nnoremap <silent><buffer><expr> S
+  \ defx#do_action('toggle_sort', 'time')
+  nnoremap <silent><buffer><expr> md
+  \ defx#do_action('remove')
+  nnoremap <silent><buffer><expr> mr
+  \ defx#do_action('rename')
+  nnoremap <silent><buffer><expr> !
+  \ defx#do_action('execute_command')
+  nnoremap <silent><buffer><expr> x
+  \ defx#do_action('execute_system')
+  nnoremap <silent><buffer><expr> yy
+  \ defx#do_action('yank_path')
+  nnoremap <silent><buffer><expr> .
+  \ defx#do_action('toggle_ignored_files')
+  nnoremap <silent><buffer><expr> ;
+  \ defx#do_action('repeat')
+  nnoremap <silent><buffer><expr> h
+  \ defx#do_action('cd', ['..'])
+  nnoremap <silent><buffer><expr> ~
+  \ defx#do_action('cd')
+  nnoremap <silent><buffer><expr> q
+  \ defx#do_action('quit')
+  nnoremap <silent><buffer><expr> <Space>
+  \ defx#do_action('toggle_select') . 'j'
+  nnoremap <silent><buffer><expr> *
+  \ defx#do_action('toggle_select_all')
+  nnoremap <silent><buffer><expr> j
+  \ line('.') == line('$') ? 'gg' : 'j'
+  nnoremap <silent><buffer><expr> k
+  \ line('.') == 1 ? 'G' : 'k'
+  nnoremap <silent><buffer><expr> r
+  \ defx#do_action('redraw')
+  nnoremap <silent><buffer><expr> <C-g>
+  \ defx#do_action('print')
+  nnoremap <silent><buffer><expr> cd
+  \ defx#do_action('change_vim_cwd')
+endfunction
 
 " tagbar
 nmap <F8> :TagbarToggle<CR>
-nmap <F9> :%!python -m json.tool<CR>
 
 " NeoComplete
 let g:neocomplete#enable_at_startup = 1