diff --git a/cmd/appherder-gui/main.go b/cmd/appherder-gui/main.go
new file mode 100644
index 0000000..4e3f835
--- /dev/null
+++ b/cmd/appherder-gui/main.go
@@ -0,0 +1,35 @@
+//go:build gtk
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/alyraffauf/appherder/internal/appherder"
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gio/v2"
+)
+
+var version = "dev"
+
+func main() {
+	app, err := appherder.NewApp()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	appID := "io.github.alyraffauf.AppHerder"
+	gtkApp := adw.NewApplication(appID, gio.ApplicationFlagsNone)
+	gtkApp.SetVersion(version)
+
+	gtkApp.ConnectActivate(func() {
+		window := newMainWindow(gtkApp, app)
+		window.Present()
+	})
+
+	if code := gtkApp.Run(nil); code > 0 {
+		os.Exit(code)
+	}
+}
diff --git a/cmd/appherder-gui/main_window.go b/cmd/appherder-gui/main_window.go
new file mode 100644
index 0000000..3b66cff
--- /dev/null
+++ b/cmd/appherder-gui/main_window.go
@@ -0,0 +1,609 @@
+//go:build gtk
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"path/filepath"
+	"strings"
+
+	"github.com/alyraffauf/appherder/internal/appherder"
+	"github.com/diamondburned/gotk4-adwaita/pkg/adw"
+	"github.com/diamondburned/gotk4/pkg/gio/v2"
+	"github.com/diamondburned/gotk4/pkg/glib/v2"
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"github.com/diamondburned/gotk4/pkg/pango"
+)
+
+type mainWindow struct {
+	*adw.ApplicationWindow
+
+	app        appherder.App
+	split      *adw.NavigationSplitView
+	apps       []appherder.AppInfo
+	list       *gtk.ListBox
+	installBtn *gtk.MenuButton
+	menuBtn    *gtk.MenuButton
+	busy       int
+}
+
+func newMainWindow(gtkApp *adw.Application, app appherder.App) *mainWindow {
+	win := &mainWindow{
+		ApplicationWindow: adw.NewApplicationWindow(&gtkApp.Application),
+		app:               app,
+		split:             adw.NewNavigationSplitView(),
+		list:              gtk.NewListBox(),
+		installBtn:        gtk.NewMenuButton(),
+		menuBtn:           gtk.NewMenuButton(),
+	}
+
+	win.SetTitle("AppHerder")
+	win.SetDefaultSize(760, 520)
+	win.installActions()
+
+	win.split.SetShowContent(true)
+	win.split.SetMinSidebarWidth(260)
+	win.split.SetMaxSidebarWidth(300)
+	win.split.SetSidebar(adw.NewNavigationPage(win.sidebarView(), "AppHerder"))
+	win.split.SetContent(adw.NewNavigationPage(emptyDetailsPage(), "AppHerder"))
+	win.installBreakpoints()
+
+	win.SetContent(win.split)
+
+	win.loadApps()
+	return win
+}
+
+func (w *mainWindow) installBreakpoints() {
+	condition := adw.NewBreakpointConditionLength(adw.BreakpointConditionMaxWidth, 600, adw.LengthUnitSp)
+	breakpoint := adw.NewBreakpoint(condition)
+	breakpoint.AddSetterDirect(w.split.Object, "collapsed", glib.NewValue(true))
+	breakpoint.AddSetterDirect(w.split.Object, "show-content", glib.NewValue(false))
+	w.AddBreakpoint(breakpoint)
+}
+
+func (w *mainWindow) sidebarView() *adw.ToolbarView {
+	title := adw.NewWindowTitle("AppHerder", "")
+	header := adw.NewHeaderBar()
+	header.SetShowEndTitleButtons(false)
+	header.SetTitleWidget(title)
+	header.PackStart(w.installBtn)
+	header.PackEnd(w.menuBtn)
+
+	w.list.AddCSSClass("navigation-sidebar")
+	w.list.SetSelectionMode(gtk.SelectionSingle)
+	w.list.ConnectRowActivated(func(row *gtk.ListBoxRow) {
+		w.activateAppRow(row)
+	})
+	w.list.ConnectRowSelected(func(row *gtk.ListBoxRow) {
+		w.selectAppRow(row)
+	})
+
+	scroller := gtk.NewScrolledWindow()
+	scroller.SetPolicy(gtk.PolicyNever, gtk.PolicyAutomatic)
+	scroller.SetChild(w.list)
+	scroller.SetVExpand(true)
+
+	toolbar := adw.NewToolbarView()
+	toolbar.AddTopBar(header)
+	toolbar.SetContent(scroller)
+	return toolbar
+}
+
+func emptyDetailsPage() *adw.ToolbarView {
+	header := adw.NewHeaderBar()
+
+	empty := adw.NewStatusPage()
+	empty.SetIconName("application-x-executable-symbolic")
+	empty.SetTitle("No AppImage Selected")
+	empty.SetDescription("Select an installed AppImage to view details.")
+
+	toolbar := adw.NewToolbarView()
+	toolbar.AddTopBar(header)
+	toolbar.SetContent(empty)
+	return toolbar
+}
+
+func (w *mainWindow) installActions() {
+	w.installBtn.SetIconName("list-add-symbolic")
+	w.installBtn.SetTooltipText("Install AppImage")
+	installMenu := gio.NewMenu()
+	installMenu.Append("Install from File", "win.install-file")
+	installMenu.Append("Install from URL", "win.install-url")
+	w.installBtn.SetMenuModel(installMenu)
+
+	w.menuBtn.SetIconName("open-menu-symbolic")
+	w.menuBtn.SetTooltipText("Main Menu")
+
+	menu := gio.NewMenu()
+	updateSection := gio.NewMenu()
+	updateSection.Append("Update All", "win.apply-upgrades")
+	menu.AppendSection("", updateSection)
+	aboutSection := gio.NewMenu()
+	aboutSection.Append("About AppHerder", "win.about")
+	menu.AppendSection("", aboutSection)
+	w.menuBtn.SetMenuModel(menu)
+
+	w.addAction("apply-upgrades", w.applyUpgrades)
+	w.addAction("install-file", w.promptInstallFile)
+	w.addAction("install-url", w.promptInstallURL)
+	w.addAction("about", w.showAbout)
+}
+
+func (w *mainWindow) addAction(name string, activate func()) {
+	action := gio.NewSimpleAction(name, nil)
+	action.ConnectActivate(func(parameter *glib.Variant) {
+		activate()
+	})
+	w.AddAction(action)
+}
+
+func (w *mainWindow) showAbout() {
+	about := adw.NewAboutDialog()
+	about.SetApplicationName("AppHerder")
+	about.SetApplicationIcon("application-x-executable-symbolic")
+	about.SetVersion(version)
+	about.SetDeveloperName("Aly Raffauf")
+	about.SetDevelopers([]string{"Aly Raffauf"})
+	about.SetComments("Manage AppImages installed in your home directory.")
+	about.SetWebsite("https://github.com/alyraffauf/appherder")
+	about.SetIssueURL("https://github.com/alyraffauf/appherder/issues")
+	about.SetLicenseType(gtk.LicenseGPL30)
+	about.Present(w)
+}
+
+func (w *mainWindow) loadApps() {
+	w.run("Refreshing app list", func() (string, error) {
+		infos, err := w.app.List()
+		if err != nil {
+			return "", err
+		}
+		w.idle(func() {
+			w.renderApps(infos)
+		})
+		return "", nil
+	})
+}
+
+func (w *mainWindow) renderApps(infos []appherder.AppInfo) {
+	w.apps = infos
+	w.list.RemoveAll()
+	if len(infos) == 0 {
+		w.apps = nil
+		w.split.SetContent(adw.NewNavigationPage(emptyDetailsPage(), "AppHerder"))
+		return
+	}
+	for i, info := range infos {
+		w.list.Append(appListRow(info))
+		if i == 0 {
+			w.showDetails(info, false)
+		}
+	}
+	if first := w.list.RowAtIndex(0); first != nil {
+		w.list.SelectRow(first)
+	}
+}
+
+func (w *mainWindow) activateAppRow(row *gtk.ListBoxRow) {
+	w.showDetailsForRow(row, true)
+}
+
+func (w *mainWindow) selectAppRow(row *gtk.ListBoxRow) {
+	w.showDetailsForRow(row, false)
+}
+
+func (w *mainWindow) showDetailsForRow(row *gtk.ListBoxRow, reveal bool) {
+	if row == nil {
+		return
+	}
+	index := row.Index()
+	if index < 0 || index >= len(w.apps) {
+		return
+	}
+	w.showDetails(w.apps[index], reveal)
+}
+
+func appListRow(info appherder.AppInfo) *gtk.ListBoxRow {
+	row := gtk.NewListBoxRow()
+	row.SetActivatable(true)
+	row.SetSelectable(true)
+
+	box := gtk.NewBox(gtk.OrientationHorizontal, 12)
+	box.SetMarginTop(8)
+	box.SetMarginBottom(8)
+	box.SetMarginStart(12)
+	box.SetMarginEnd(12)
+
+	icon := appIcon(info, 36)
+	icon.SetVAlign(gtk.AlignCenter)
+	box.Append(icon)
+
+	name := gtk.NewLabel(info.Name)
+	name.SetXAlign(0)
+	name.SetEllipsize(pango.EllipsizeEnd)
+	name.SetLines(1)
+	name.SetHExpand(true)
+	name.SetVAlign(gtk.AlignCenter)
+	box.Append(name)
+
+	row.SetChild(box)
+	return row
+}
+
+func appSummary(info appherder.AppInfo) string {
+	if info.Filename != "" {
+		return info.Filename
+	}
+	return info.AppID
+}
+
+func (w *mainWindow) showDetails(info appherder.AppInfo, reveal bool) {
+	w.split.SetContent(adw.NewNavigationPage(w.appDetailsView(info), info.Name))
+	if reveal {
+		w.split.SetShowContent(true)
+	}
+}
+
+func (w *mainWindow) appDetailsView(info appherder.AppInfo) *adw.ToolbarView {
+	header := adw.NewHeaderBar()
+
+	hero := gtk.NewBox(gtk.OrientationVertical, 8)
+	hero.SetMarginTop(24)
+	hero.SetMarginBottom(20)
+	hero.SetMarginStart(24)
+	hero.SetMarginEnd(24)
+	hero.SetHAlign(gtk.AlignCenter)
+	hero.Append(appIcon(info, 88))
+
+	summary := gtk.NewBox(gtk.OrientationVertical, 4)
+	summary.SetHAlign(gtk.AlignCenter)
+
+	name := gtk.NewLabel(info.Name)
+	name.AddCSSClass("title-1")
+	name.SetEllipsize(pango.EllipsizeEnd)
+	name.SetMaxWidthChars(28)
+	name.SetLines(1)
+
+	subtitle := gtk.NewLabel(appSummary(info))
+	subtitle.SetWrap(true)
+	subtitle.AddCSSClass("dim-label")
+	subtitle.SetEllipsize(pango.EllipsizeEnd)
+	subtitle.SetMaxWidthChars(34)
+	subtitle.SetLines(1)
+
+	summary.Append(name)
+	summary.Append(subtitle)
+
+	actions := gtk.NewBox(gtk.OrientationHorizontal, 8)
+	actions.SetMarginTop(10)
+
+	launch := gtk.NewButtonWithLabel("Launch")
+	launch.AddCSSClass("pill")
+	launch.AddCSSClass("suggested-action")
+	launch.ConnectClicked(func() { w.launchApp(info) })
+	actions.Append(launch)
+
+	remove := gtk.NewButtonWithLabel("Remove")
+	remove.AddCSSClass("pill")
+	remove.AddCSSClass("destructive-action")
+	remove.ConnectClicked(func() { w.confirmUninstall(info) })
+	actions.Append(remove)
+
+	summary.Append(actions)
+	hero.Append(summary)
+
+	details := adw.NewPreferencesGroup()
+	details.SetTitle("Details")
+
+	for _, field := range []struct {
+		label string
+		value string
+	}{
+		{"Version", orDash(info.Version)},
+		{"Size", sizeOrDash(info.Size)},
+		{"Update Source", sourceLabel(info.Source)},
+		{"Signature", signatureLabel(info.Signature)},
+		{"App ID", info.AppID},
+		{"File", orDash(info.Filename)},
+	} {
+		row := adw.NewActionRow()
+		row.SetTitle(field.label)
+		row.SetSubtitle(field.value)
+		details.Add(row)
+	}
+
+	content := gtk.NewBox(gtk.OrientationVertical, 0)
+	content.Append(hero)
+
+	clamp := adw.NewClamp()
+	clamp.SetMaximumSize(560)
+	clamp.SetTighteningThreshold(520)
+	clamp.SetChild(details)
+	clamp.SetMarginStart(24)
+	clamp.SetMarginEnd(24)
+	clamp.SetMarginBottom(24)
+	content.Append(clamp)
+
+	scroller := gtk.NewScrolledWindow()
+	scroller.SetChild(content)
+	scroller.SetVExpand(true)
+
+	toolbar := adw.NewToolbarView()
+	toolbar.AddTopBar(header)
+	toolbar.SetContent(scroller)
+	return toolbar
+}
+
+func appIcon(info appherder.AppInfo, size int) *gtk.Image {
+	if info.Icon != "" && strings.HasPrefix(info.Icon, "/") {
+		image := gtk.NewImageFromFile(info.Icon)
+		image.SetPixelSize(size)
+		image.SetSizeRequest(size, size)
+		return image
+	}
+	iconName := info.Icon
+	if iconName == "" {
+		iconName = "application-x-executable-symbolic"
+	}
+	image := gtk.NewImageFromIconName(iconName)
+	image.SetPixelSize(size)
+	image.SetSizeRequest(size, size)
+	return image
+}
+
+func (w *mainWindow) applyUpgrades() {
+	w.run("Installing updates", func() (string, error) {
+		checks, err := w.app.CheckUpgrades(context.Background())
+		if err != nil {
+			return "", err
+		}
+		applied := w.app.ApplyUpgrades(context.Background(), checks)
+		upgraded, failed := summarizeApplied(applied)
+		w.idle(w.loadApps)
+		if upgraded == 0 && failed == 0 {
+			return "Everything is up to date", nil
+		}
+		return fmt.Sprintf("%d app%s upgraded, %d upgrade%s failed", upgraded, plural(upgraded), failed, plural(failed)), nil
+	})
+}
+
+func (w *mainWindow) launchApp(info appherder.AppInfo) {
+	w.run("Launching "+info.Name, func() (string, error) {
+		if err := w.app.Launch(appKey(info)); err != nil {
+			return "", err
+		}
+		return "", nil
+	})
+}
+
+func (w *mainWindow) promptInstallFile() {
+	dialog := gtk.NewFileDialog()
+	dialog.SetTitle("Install AppImage")
+
+	filter := gtk.NewFileFilter()
+	filter.SetName("AppImages")
+	filter.AddSuffix("appimage")
+	filter.AddSuffix("AppImage")
+
+	allFiles := gtk.NewFileFilter()
+	allFiles.SetName("All Files")
+	allFiles.AddPattern("*")
+
+	filters := gio.NewListStore(gtk.GTypeFileFilter)
+	filters.Append(filter.Object)
+	filters.Append(allFiles.Object)
+	dialog.SetFilters(filters)
+	dialog.SetDefaultFilter(filter)
+
+	dialog.Open(context.Background(), &w.Window, func(result gio.AsyncResulter) {
+		file, err := dialog.OpenFinish(result)
+		if err != nil || file == nil {
+			return
+		}
+		path := file.Path()
+		if path == "" {
+			w.showError("Cannot Install File", "Selected file has no local path.")
+			return
+		}
+		w.install(path)
+	})
+}
+
+func (w *mainWindow) promptInstallURL() {
+	entry := gtk.NewEntry()
+	entry.SetPlaceholderText("https://example.com/app.AppImage")
+	entry.SetHExpand(true)
+
+	dialog := adw.NewAlertDialog("Install from URL", "Enter an HTTP or HTTPS AppImage URL.")
+	dialog.SetExtraChild(entry)
+	dialog.AddResponse("cancel", "Cancel")
+	dialog.AddResponse("install", "Install")
+	dialog.SetCloseResponse("cancel")
+	dialog.SetDefaultResponse("install")
+	dialog.ConnectResponse(func(response string) {
+		if response != "install" {
+			return
+		}
+		target := strings.TrimSpace(entry.Text())
+		if target == "" {
+			w.showError("Cannot Install URL", "Enter a URL to install.")
+			return
+		}
+		if !looksLikeURL(target) {
+			w.showError("Cannot Install URL", "Enter an HTTP or HTTPS URL.")
+			return
+		}
+		w.install(target)
+	})
+	dialog.Present(w)
+}
+
+func (w *mainWindow) install(target string) {
+	w.run("Installing AppImage", func() (string, error) {
+		var name string
+		var err error
+		if looksLikeURL(target) {
+			name, err = w.app.InstallFromURL(context.Background(), target)
+		} else {
+			name, err = w.app.Install(target)
+		}
+		if err != nil {
+			return "", err
+		}
+		w.idle(w.loadApps)
+		return fmt.Sprintf("Installed %s", name), nil
+	})
+}
+
+func (w *mainWindow) confirmUninstall(info appherder.AppInfo) {
+	dialog := adw.NewAlertDialog("Remove "+info.Name+"?", "This removes the AppImage, launcher, icon, and appherder metadata.")
+	dialog.AddResponse("cancel", "Cancel")
+	dialog.AddResponse("remove", "Remove")
+	dialog.SetCloseResponse("cancel")
+	dialog.SetDefaultResponse("cancel")
+	dialog.SetResponseAppearance("remove", adw.ResponseDestructive)
+	dialog.ConnectResponse(func(response string) {
+		if response == "remove" {
+			w.uninstall(info)
+		}
+	})
+	dialog.Present(w)
+}
+
+func (w *mainWindow) uninstall(info appherder.AppInfo) {
+	w.run("Removing "+info.Name, func() (string, error) {
+		if err := w.app.Uninstall(appKey(info), false); err != nil {
+			return "", err
+		}
+		w.idle(w.loadApps)
+		return "Removed " + info.Name, nil
+	})
+}
+
+func (w *mainWindow) run(_ string, fn func() (string, error)) {
+	w.setBusy(1)
+	go func() {
+		_, err := fn()
+		w.idle(func() {
+			w.setBusy(-1)
+			if err != nil {
+				w.showError("Operation Failed", err.Error())
+				return
+			}
+		})
+	}()
+}
+
+func (w *mainWindow) setBusy(delta int) {
+	w.busy += delta
+	if w.busy < 0 {
+		w.busy = 0
+	}
+	sensitive := w.busy == 0
+	w.installBtn.SetSensitive(sensitive)
+	w.menuBtn.SetSensitive(sensitive)
+}
+
+func (w *mainWindow) idle(fn func()) {
+	glib.IdleAdd(fn)
+}
+
+func (w *mainWindow) showError(title, message string) {
+	dialog := adw.NewAlertDialog(title, message)
+	dialog.AddResponse("close", "Close")
+	dialog.SetCloseResponse("close")
+	dialog.SetDefaultResponse("close")
+	dialog.Present(w)
+}
+
+func looksLikeURL(s string) bool {
+	parsed, err := url.Parse(s)
+	return err == nil && (parsed.Scheme == "http" || parsed.Scheme == "https") && parsed.Host != ""
+}
+
+func summarizeApplied(applied []appherder.UpgradeApplied) (upgraded, failed int) {
+	for _, app := range applied {
+		if app.Err != nil {
+			failed++
+		} else {
+			upgraded++
+		}
+	}
+	return upgraded, failed
+}
+
+func plural(n int) string {
+	if n == 1 {
+		return ""
+	}
+	return "s"
+}
+
+func orDash(s string) string {
+	if s == "" {
+		return "-"
+	}
+	return s
+}
+
+func humanSize(bytes int64) string {
+	const unit = 1024
+	if bytes < unit {
+		return fmt.Sprintf("%d B", bytes)
+	}
+	div, exp := int64(unit), 0
+	for scaled := bytes / unit; scaled >= unit; scaled /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf("%.1f %cB", float64(bytes)/float64(div), "KMGTPE"[exp])
+}
+
+func appKey(info appherder.AppInfo) string {
+	if info.AppID != "" {
+		return info.AppID
+	}
+	if info.Filename == "" {
+		return appherder.NormalizeAppName(info.Name)
+	}
+	return strings.TrimSuffix(filepath.Base(info.Filename), filepath.Ext(info.Filename))
+}
+
+func sizeOrDash(bytes int64) string {
+	if bytes <= 0 {
+		return "-"
+	}
+	return humanSize(bytes)
+}
+
+func sourceLabel(source string) string {
+	switch source {
+	case "", "none":
+		return "No update source"
+	case "github":
+		return "GitHub"
+	case "gitlab":
+		return "GitLab"
+	case "zsync":
+		return "zsync"
+	case "static":
+		return "Static URL"
+	default:
+		return source
+	}
+}
+
+func signatureLabel(signature string) string {
+	switch signature {
+	case "pinned":
+		return "Pinned signature"
+	case "signed":
+		return "Signed"
+	case "", "none":
+		return "Unsigned"
+	default:
+		return signature
+	}
+}
diff --git a/flake.nix b/flake.nix
index 8c5b50d..50ec178 100644
--- a/flake.nix
+++ b/flake.nix
@@ -33,8 +33,18 @@
           packages = with pkgs; [
             go
             dwarfs
+            pkg-config
+            glib
+            gobject-introspection
+            gtk4
+            libadwaita
             self.formatter.${system}
           ];
+
+          shellHook = ''
+            export GOCACHE="''${XDG_CACHE_HOME:-$HOME/.cache}/appherder/go-build"
+            mkdir -p "$GOCACHE"
+          '';
         };
       }
     );
@@ -42,9 +52,16 @@
     formatter = forEachSupportedSystem ({pkgs, ...}: pkgs.alejandra);
 
     packages = forEachSupportedSystem (
-      {pkgs, ...}: {
-        default = pkgs.callPackage ./package.nix {};
-      }
+      {pkgs, ...}: let
+        appherder = pkgs.callPackage ./package.nix {};
+      in
+        {
+          default = appherder;
+          inherit appherder;
+        }
+        // lib.optionalAttrs pkgs.stdenv.isLinux {
+          appherder-gui = pkgs.callPackage ./package-gui.nix {};
+        }
     );
   };
 }
diff --git a/go.mod b/go.mod
index 7719c65..b21ba69 100644
--- a/go.mod
+++ b/go.mod
@@ -7,11 +7,14 @@ require (
 	github.com/ProtonMail/go-crypto v1.4.1
 	github.com/adrg/xdg v0.5.3
 	github.com/alyraffauf/goxdgdesktop v0.1.0
+	github.com/diamondburned/gotk4-adwaita/pkg v0.0.0-20250703085337-e94555b846b6
+	github.com/diamondburned/gotk4/pkg v0.3.2-0.20250703063411-16654385f59a
 	github.com/pelletier/go-toml/v2 v2.2.4
 	github.com/spf13/cobra v1.10.2
 )
 
 require (
+	github.com/KarpelesLab/weak v0.1.1 // indirect
 	github.com/cloudflare/circl v1.6.3 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 // indirect
@@ -21,6 +24,8 @@ require (
 	github.com/rasky/go-lzo v0.0.0-20200203143853-96a758eda86e // indirect
 	github.com/spf13/pflag v1.0.10 // indirect
 	github.com/ulikunitz/xz v0.5.15 // indirect
+	go4.org/unsafe/assume-no-moving-gc v0.0.0-20231121144256-b99613f794b6 // indirect
 	golang.org/x/crypto v0.53.0 // indirect
+	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
 	golang.org/x/sys v0.46.0 // indirect
 )
diff --git a/go.sum b/go.sum
index 513098a..5dd731a 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/CalebQ42/squashfs v1.4.1 h1:tBcFMQSRQvWcY50e9r9cv2uVzNf06fcUhly0LeZg8bI=
 github.com/CalebQ42/squashfs v1.4.1/go.mod h1:/As5wg6ScFFaab9SaNFNHyCOsd73Q5IFPOFJCVnwWzQ=
+github.com/KarpelesLab/weak v0.1.1 h1:fNnlPo3aypS9tBzoEQluY13XyUfd/eWaSE/vMvo9s4g=
+github.com/KarpelesLab/weak v0.1.1/go.mod h1:pzXsWs5f2bf+fpgHayTlBE1qJpO3MpJKo5sRaLu1XNw=
 github.com/ProtonMail/go-crypto v1.4.1 h1:9RfcZHqEQUvP8RzecWEUafnZVtEvrBVL9BiF67IQOfM=
 github.com/ProtonMail/go-crypto v1.4.1/go.mod h1:e1OaTyu5SYVrO9gKOEhTc+5UcXtTUa+P3uLudwcgPqo=
 github.com/adrg/xdg v0.5.3 h1:xRnxJXne7+oWDatRhR1JLnvuccuIeCoBu2rtuLqQB78=
@@ -11,6 +13,10 @@ github.com/cloudflare/circl v1.6.3/go.mod h1:2eXP6Qfat4O/Yhh8BznvKnJ+uzEoTQ6jVKJ
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/diamondburned/gotk4-adwaita/pkg v0.0.0-20250703085337-e94555b846b6 h1:WzOC3KtvrC1hJMz3fbJBg0Ye50nt4Tafor+a/bBHNEA=
+github.com/diamondburned/gotk4-adwaita/pkg v0.0.0-20250703085337-e94555b846b6/go.mod h1:ZzYiyPe0TqsukfPHi0sK/WwKzm0wIJdSRylLnuvAZNw=
+github.com/diamondburned/gotk4/pkg v0.3.2-0.20250703063411-16654385f59a h1:dN2jYYZ71hFhoKFSn24pQdKWLZb/XDydBt8pEIkFjJo=
+github.com/diamondburned/gotk4/pkg v0.3.2-0.20250703063411-16654385f59a/go.mod h1:O9K8+PGNFGJpAu8+u5D2Sn5Wae4hxWzHB+AeZNbV/2Q=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51 h1:Z9n2FFNUXsshfwJMBgNA0RU6/i7WVaAegv3PtuIHPMs=
@@ -38,8 +44,12 @@ github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8
 github.com/ulikunitz/xz v0.5.15 h1:9DNdB5s+SgV3bQ2ApL10xRc35ck0DuIX/isZvIk+ubY=
 github.com/ulikunitz/xz v0.5.15/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
+go4.org/unsafe/assume-no-moving-gc v0.0.0-20231121144256-b99613f794b6 h1:lGdhQUN/cnWdSH3291CUuxSEqc+AsGTiDxPP3r2J0l4=
+go4.org/unsafe/assume-no-moving-gc v0.0.0-20231121144256-b99613f794b6/go.mod h1:FftLjUGFEDu5k8lt0ddY+HcrH/qU/0qk+H8j9/nTl3E=
 golang.org/x/crypto v0.53.0 h1:QZ4Muo8THX6CizN2vPPd5fBGHyogrdK9fG4wLPFUsto=
 golang.org/x/crypto v0.53.0/go.mod h1:DNLU434OwVakk9PzuwV8w62mAJpRJL3vsgcfp4Qnsio=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
 golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
diff --git a/justfile b/justfile
new file mode 100644
index 0000000..0aea9fe
--- /dev/null
+++ b/justfile
@@ -0,0 +1,25 @@
+set dotenv-load
+
+GOFLAGS := "-trimpath"
+GOCACHE := `printf '%s/appherder/go-build' "${XDG_CACHE_HOME:-$HOME/.cache}"`
+
+default:
+    just --list
+
+build: build-cli build-ui
+
+build-cli:
+    mkdir -p '{{GOCACHE}}'
+    nix develop -c env GOCACHE='{{GOCACHE}}' GOSUMDB=off go build {{GOFLAGS}} -o ./appherder ./cmd/appherder
+
+build-ui:
+    mkdir -p '{{GOCACHE}}'
+    nix develop -c env GOCACHE='{{GOCACHE}}' GOSUMDB=off go build {{GOFLAGS}} -tags gtk -o ./appherder-gui ./cmd/appherder-gui
+
+test:
+    mkdir -p '{{GOCACHE}}'
+    nix develop -c env GOCACHE='{{GOCACHE}}' GOSUMDB=off go test ./...
+
+test-ui:
+    mkdir -p '{{GOCACHE}}'
+    nix develop -c env GOCACHE='{{GOCACHE}}' GOSUMDB=off go test -tags gtk ./cmd/appherder-gui
diff --git a/package-gui.nix b/package-gui.nix
new file mode 100644
index 0000000..e659adb
--- /dev/null
+++ b/package-gui.nix
@@ -0,0 +1,38 @@
+{
+  buildGoModule,
+  glib,
+  gtk4,
+  lib,
+  libadwaita,
+  pkg-config,
+  wrapGAppsHook4,
+}: let
+  version = "dev";
+in
+  buildGoModule {
+    pname = "appherder-gui";
+    inherit version;
+    src = ./.;
+    vendorHash = "sha256-YoNtqb5dflJNCZBstAQxP458ktpUighC8uYuqFWjTyo=";
+    subPackages = ["cmd/appherder-gui"];
+    tags = ["gtk"];
+    ldflags = ["-X main.version=${version}"];
+
+    nativeBuildInputs = [
+      pkg-config
+      wrapGAppsHook4
+    ];
+
+    buildInputs = [
+      glib
+      gtk4
+      libadwaita
+    ];
+
+    meta = {
+      description = "GTK/libadwaita interface for AppHerder";
+      license = lib.licenses.gpl3Only;
+      mainProgram = "appherder-gui";
+      platforms = lib.platforms.linux;
+    };
+  }