diff --git a/after/ftplugin/json.vim b/after/ftplugin/json.vim
new file mode 100644
index 0000000..90db3ec
--- /dev/null
+++ b/after/ftplugin/json.vim
@@ -0,0 +1,6 @@
+" let the initial folding state be that all folds are closed.
+set foldlevel=0
+
+" Use nvim-treesitter for folding
+set foldmethod=expr
+set foldexpr=nvim_treesitter#foldexpr()
diff --git a/lua/config/treesitter.lua b/lua/config/treesitter.lua
index 92759d3..ee07b83 100644
--- a/lua/config/treesitter.lua
+++ b/lua/config/treesitter.lua
@@ -1,5 +1,5 @@
 require("nvim-treesitter.configs").setup {
-  ensure_installed = { "python", "cpp", "lua", "vim" },
+  ensure_installed = { "python", "cpp", "lua", "vim", "json" },
   ignore_install = {}, -- List of parsers to ignore installing
   highlight = {
     enable = true, -- false will disable the whole extension
diff --git a/plugin/command.vim b/plugin/command.vim
index 5ed7b73..68b11f4 100644
--- a/plugin/command.vim
+++ b/plugin/command.vim
@@ -45,3 +45,6 @@ function! s:md_to_pdf() abort
     echoerr "Error running command"
   endif
 endfunction
+
+" json format
+command! -range JSONFormat <line1>,<line2>!python -m json.tool