diff --git a/cmd/run.go b/cmd/run.go
index 20e864b7..4218cf81 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -4,9 +4,12 @@ import (
 	"ags/lib"
 	"fmt"
 	"io"
+	"log"
 	"os"
+	"os/exec"
 	"path/filepath"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/spf13/cobra"
 )
 
@@ -15,6 +18,7 @@ var (
 	targetDir string
 	logFile   string
 	args      []string
+	watch     bool
 )
 
 var runCommand = &cobra.Command{
@@ -48,6 +52,7 @@ var runCommand = &cobra.Command{
 func init() {
 	f := runCommand.Flags()
 	f.BoolVar(&gtk4, "gtk4", false, "preload Gtk4LayerShell")
+	f.BoolVar(&watch, "watch", false, "restart gjs on file changes")
 	f.StringVarP(&targetDir, "directory", "d", defaultConfigDir(),
 		`directory to search for an "app" entry file
 when no positional argument is given
@@ -115,19 +120,79 @@ func run(infile string) {
 
 	args = append([]string{"-m", outfile}, args...)
 	stdout, stderr, file := logging()
-	gjs := lib.Exec("gjs", args...)
-	gjs.Stdin = os.Stdin
-	gjs.Dir = filepath.Dir(infile)
+	if file != nil {
+		defer file.Close()
+	}
+
+	var gjs *exec.Cmd
+	gjsStart := func() (*exec.Cmd, error) {
+		if gjs != nil {
+			if err := gjs.Process.Kill(); err != nil {
+				log.Printf("Failed to kill process: %v", err)
+			}
+			_ = gjs.Wait()
+		}
+
+		gjs = lib.Exec("gjs", args...)
+		gjs.Stdin = os.Stdin
+		gjs.Dir = filepath.Dir(infile)
 
-	gjs.Stdout = stdout
-	gjs.Stderr = stderr
+		gjs.Stdout = stdout
+		gjs.Stderr = stderr
 
-	// TODO: watch and restart
-	if err := gjs.Run(); err != nil {
+		err := gjs.Start()
+
+		return gjs, err
+	}
+
+	if err := watchRun(gjsStart); err != nil {
 		lib.Err(err)
 	}
+}
 
-	if file != nil {
-		file.Close()
+func watchRun(gjsStart func() (*exec.Cmd, error)) error {
+	cmd, err := gjsStart()
+	if err != nil {
+		return err
 	}
+	if !watch {
+		return cmd.Wait()
+	}
+
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return err
+	}
+	defer watcher.Close()
+
+	go func() {
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return
+				}
+				log.Println("event:", event)
+				if event.Has(fsnotify.Write) {
+					log.Println("modified file:", event.Name)
+					_, _ = gjsStart()
+				}
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return
+				}
+				log.Println("error:", err)
+			}
+		}
+	}()
+
+	err = watcher.Add(targetDir)
+	if err != nil {
+		return err
+	}
+
+	// Block main goroutine forever.
+	<-make(chan struct{})
+
+	return nil
 }
diff --git a/go.mod b/go.mod
index ed25d418..255fb856 100644
--- a/go.mod
+++ b/go.mod
@@ -4,12 +4,13 @@ go 1.22.2
 
 require (
 	github.com/evanw/esbuild v0.24.0
+	github.com/fsnotify/fsnotify v1.8.0
 	github.com/spf13/cobra v1.8.1
+	github.com/titanous/json5 v1.0.0
 )
 
 require (
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/titanous/json5 v1.0.0 // indirect
-	golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
+	golang.org/x/sys v0.27.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 96075725..75c92b19 100644
--- a/go.sum
+++ b/go.sum
@@ -1,8 +1,14 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/evanw/esbuild v0.24.0 h1:GZ78naTLp7FKr+K7eNuM/SLs5maeiHYRPsTg6kmdsSE=
 github.com/evanw/esbuild v0.24.0/go.mod h1:D2vIQZqV/vIf/VRHtViaUtViZmG7o+kKmlBfVQuRi48=
+github.com/fsnotify/fsnotify v1.8.0 h1:dAwr6QBTBZIkG8roQaJjGof0pp0EeF+tNV7YBP3F/8M=
+github.com/fsnotify/fsnotify v1.8.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/robertkrimen/otto v0.2.1 h1:FVP0PJ0AHIjC+N4pKCG9yCDz6LHNPCwi/GKID5pGGF0=
+github.com/robertkrimen/otto v0.2.1/go.mod h1:UPwtJ1Xu7JrLcZjNWN8orJaM5n5YEtqL//farB5FlRY=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/cobra v1.8.1 h1:e5/vxKd/rZsfSJMUX1agtjeTDf+qv1/JdBF8gg5k9ZM=
 github.com/spf13/cobra v1.8.1/go.mod h1:wHxEcudfqmLYa8iTfL+OuZPbBZkmvliBWKIezN3kD9Y=
@@ -10,7 +16,12 @@ github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/titanous/json5 v1.0.0 h1:hJf8Su1d9NuI/ffpxgxQfxh/UiBFZX7bMPid0rIL/7s=
 github.com/titanous/json5 v1.0.0/go.mod h1:7JH1M8/LHKc6cyP5o5g3CSaRj+mBrIimTxzpvmckH8c=
-golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.27.0 h1:wBqf8DvsY9Y/2P8gAfPDEYNuS30J4lPHJxXSb/nJZ+s=
+golang.org/x/sys v0.27.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/text v0.4.0 h1:BrVqGRd7+k1DiOgtnFvAkoQEWQvBc25ouMJM6429SFg=
+golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/sourcemap.v1 v1.0.5 h1:inv58fC9f9J3TK2Y2R1NPntXEn3/wjWHkonhIUODNTI=
+gopkg.in/sourcemap.v1 v1.0.5/go.mod h1:2RlvNNSMglmRrcvhfuzp4hQHwOtjxlbjX7UPY/GXb78=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/nix/default.nix b/nix/default.nix
index 04e13ebf..4fac98c9 100644
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -44,7 +44,7 @@ in
       path = lib.cleanSource ../.;
     };
 
-    vendorHash = "sha256-Pw6UNT5YkDVz4HcH7b5LfOg+K3ohrBGPGB9wYGAQ9F4=";
+    vendorHash = "sha256-2CahD2POdmT4Xg+j79YBeDab9mReRB5n4DtDosM8j/I=";
     proxyVendor = true;
 
     nativeBuildInputs = [