diff --git a/go.mod b/go.mod
index 885aef9..2951f7c 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module github.com/skanehira/tson
 go 1.13
 
 require (
+	github.com/creack/pty v1.1.9
 	github.com/gdamore/tcell v1.3.0
 	github.com/gofrs/uuid v3.2.0+incompatible
 	github.com/mitchellh/go-homedir v1.1.0
diff --git a/go.sum b/go.sum
index f75ac87..0124856 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/DATA-DOG/go-sqlmock v1.3.3 h1:CWUqKXe0s8A2z6qCgkP4Kru7wC11YoAnoupUKFDnH08=
 github.com/DATA-DOG/go-sqlmock v1.3.3/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
+github.com/creack/pty v1.1.9 h1:uDmaGzcdjhF4i/plgjmEsriH11Y0o7RKapEf/LDaM3w=
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdko=
 github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
 github.com/gdamore/tcell v1.3.0 h1:r35w0JBADPZCVQijYebl6YMWWtHRqVEGt7kL2eBADRM=
diff --git a/gui/gui.go b/gui/gui.go
index b87fa6f..38ee676 100644
--- a/gui/gui.go
+++ b/gui/gui.go
@@ -9,11 +9,16 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"os/exec"
+	"os/signal"
 	"strconv"
 	"strings"
+	"syscall"
 
+	"github.com/creack/pty"
 	"github.com/gdamore/tcell"
 	"github.com/rivo/tview"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 var (
@@ -201,23 +206,26 @@ func (g *Gui) SaveJSON() {
 	g.Form(labels, "save", "save to file", "save_to_file", 7, func(values map[string]string) error {
 		file := values[labels[0]]
 		file = os.ExpandEnv(file)
+		return g.SaveJSONToFile(file)
+	})
+}
 
-		var buf bytes.Buffer
-		enc := json.NewEncoder(&buf)
-		enc.SetIndent("", "  ")
+func (g *Gui) SaveJSONToFile(file string) error {
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	enc.SetIndent("", "  ")
 
-		if err := enc.Encode(g.makeJSON(g.Tree.GetRoot())); err != nil {
-			log.Println(fmt.Sprintf("can't marshal json: %s", err))
-			return err
-		}
+	if err := enc.Encode(g.makeJSON(g.Tree.GetRoot())); err != nil {
+		log.Println(fmt.Sprintf("can't marshal json: %s", err))
+		return err
+	}
 
-		if err := ioutil.WriteFile(file, buf.Bytes(), 0666); err != nil {
-			log.Println(fmt.Sprintf("can't create file: %s", err))
-			return err
-		}
+	if err := ioutil.WriteFile(file, buf.Bytes(), 0666); err != nil {
+		log.Println(fmt.Sprintf("can't create file: %s", err))
+		return err
+	}
 
-		return nil
-	})
+	return nil
 }
 
 func (g *Gui) makeJSON(node *tview.TreeNode) interface{} {
@@ -330,6 +338,84 @@ func (g *Gui) NaviPanel() {
 	}
 }
 
+func (g *Gui) EditWithEditor() {
+	f, err := ioutil.TempFile("", "tson")
+	if err != nil {
+		log.Println(fmt.Sprintf("can't create temp file: %s", err))
+		g.Message(err.Error(), "main", func() {})
+		return
+	}
+
+	defer os.RemoveAll(f.Name())
+
+	if err := g.SaveJSONToFile(f.Name()); err != nil {
+		log.Println(fmt.Sprintf("can't write to temp file: %s", err))
+		g.Message(err.Error(), "main", func() {})
+		return
+	}
+
+	if b := g.App.Suspend(func() {
+		editor := os.Getenv("EDITOR")
+		if editor == "" {
+			log.Println(fmt.Sprintf("$EDITOR is empty: %s", err))
+			g.Message(err.Error(), "main", func() {})
+			return
+		}
+
+		cmd := exec.Command(editor, f.Name())
+
+		// Start the command with a pty.
+		ptmx, err := pty.Start(cmd)
+		if err != nil {
+			g.Message(err.Error(), "main", func() {})
+			return
+		}
+		// Make sure to close the pty at the end.
+		defer func() { _ = ptmx.Close() }() // Best effort.
+
+		// Handle pty size.
+		ch := make(chan os.Signal, 1)
+		signal.Notify(ch, syscall.SIGWINCH)
+		go func() {
+			for range ch {
+				if err := pty.InheritSize(os.Stdin, ptmx); err != nil {
+					log.Printf("can't resizing pty: %s", err)
+				}
+			}
+		}()
+		ch <- syscall.SIGWINCH // Initial resize.
+
+		// Set stdin in raw mode.
+		oldState, err := terminal.MakeRaw(int(os.Stdin.Fd()))
+		if err != nil {
+			log.Println(fmt.Sprintf("can't make terminal raw mode: %s", err))
+			g.Message(err.Error(), "main", func() {})
+			return
+		}
+		defer func() { _ = terminal.Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
+
+		// Copy stdin to the pty and the pty to stdout.
+		go func() {
+			io.Copy(ptmx, os.Stdin)
+		}()
+
+		io.Copy(os.Stdout, ptmx)
+
+		i, err := UnMarshalJSON(f)
+		if err != nil {
+			log.Println(fmt.Sprintf("can't read from file: %s", err))
+			g.Message(err.Error(), "main", func() {})
+			return
+		}
+
+		g.Tree.UpdateView(g, i)
+	}); !b {
+		log.Println(fmt.Sprintf("can't edit: %s", err))
+		g.Message(err.Error(), "main", func() {})
+		return
+	}
+}
+
 func UnMarshalJSON(in io.Reader) (interface{}, error) {
 	b, err := ioutil.ReadAll(in)
 	if err != nil {
diff --git a/gui/tree.go b/gui/tree.go
index 68d2de6..53f04bd 100644
--- a/gui/tree.go
+++ b/gui/tree.go
@@ -10,6 +10,7 @@ import (
 	"github.com/gdamore/tcell"
 	"github.com/gofrs/uuid"
 	"github.com/rivo/tview"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 const (
@@ -160,6 +161,10 @@ func (t *Tree) SetKeybindings(g *Gui) {
 			g.AddValue()
 		case '?':
 			g.NaviPanel()
+		case 'e':
+			if terminal.IsTerminal(0) {
+				g.EditWithEditor()
+			}
 		case ' ':
 			current := t.GetCurrentNode()
 			current.SetExpanded(!current.IsExpanded())