diff --git a/lib/server/pages.go b/lib/server/pages.go
index 99bd850..39db80c 100644
--- a/lib/server/pages.go
+++ b/lib/server/pages.go
@@ -24,6 +24,7 @@ func (app *App) handleIndex(ctx *gin.Context) {
 		"UploadsEnabled":   app.config.GuestUploadsEnabled && app.config.APIEnabled,
 		"MaxFileSizeBytes": app.config.GlobalMaxFileSizeBytes,
 		"MaxBoxSizeBytes":  app.config.GlobalMaxBoxSizeBytes,
+		"AppVersion":       app.appVersion,
 	})
 }
 
diff --git a/lib/server/server.go b/lib/server/server.go
index 3a85eb5..20f85ff 100644
--- a/lib/server/server.go
+++ b/lib/server/server.go
@@ -3,7 +3,9 @@ package server
 import (
 	"encoding/json"
 	"html/template"
+	"os"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"github.com/gin-contrib/gzip"
@@ -23,6 +25,7 @@ type App struct {
 	activityStore         *activity.Store
 	alertStore            *alerts.Store
 	securityGuard         *security.Guard
+	appVersion            string
 }
 
 func Run(addr string) error {
@@ -56,12 +59,14 @@ func Run(addr string) error {
 		activityStore:         activity.NewStore(filepath.Join(cfg.DBDir, "activity_log.json")),
 		alertStore:            alerts.NewStore(filepath.Join(cfg.DBDir, "alerts.json")),
 		securityGuard:         security.NewGuard(),
+		appVersion:            currentAppVersion(),
 	}
 	if err := app.reloadSecurityConfig(); err != nil {
 		return err
 	}
 
 	router := gin.Default()
+	router.Use(app.versionHeaderMiddleware())
 	router.Use(app.securityMiddleware())
 	router.NoRoute(app.handleNoRoute)
 	htmlTemplates, err := loadHTMLTemplates()
@@ -149,3 +154,18 @@ func (app *App) handleHealth(c *gin.Context) {
 		"status": "healthy",
 	})
 }
+
+func (app *App) versionHeaderMiddleware() gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		ctx.Header("X-App-Version", app.appVersion)
+		ctx.Next()
+	}
+}
+
+func currentAppVersion() string {
+	version := strings.TrimSpace(os.Getenv("APP_VERSION"))
+	if version == "" {
+		return "dev"
+	}
+	return version
+}
diff --git a/templates/index.html b/templates/index.html
index f4dc05f..1290049 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -126,6 +126,7 @@
                     <div class="win98-statusbar upload-statusbar">
                         <span id="status-text">{{ if .UploadsEnabled }}Ready · drag files anywhere onto the window{{ else }}Guest uploads are disabled{{ end }}</span>
                         <span>WarpBox</span>
+                        <span>v{{ .AppVersion }}</span>
                     </div>
                 </section>