diff --git a/cmd/web/handlers.go b/cmd/web/handlers.go
index 78f5fb9..6d113a1 100644
--- a/cmd/web/handlers.go
+++ b/cmd/web/handlers.go
@@ -5,12 +5,10 @@ import (
 )
 
 func (app *application) home(writer http.ResponseWriter, request *http.Request) {
-	baseURI := request.Host
-
 	data := templateData{ 
-		AppLinks: getAppLinks(app.tier, baseURI),
+		AppLinks: getAppLinks(app.tier, app.host),
 		Tier: app.tier,
-		BaseUri: baseURI,
+		BaseUri: app.host,
 	}
 
 	app.render(writer, request, http.StatusOK, "home.tmpl.html", data)
diff --git a/cmd/web/main.go b/cmd/web/main.go
index c440fd8..5ed21f4 100644
--- a/cmd/web/main.go
+++ b/cmd/web/main.go
@@ -5,24 +5,30 @@ import (
 	"log/slog"
 	"net/http"
 	"os"
-	"flag"
 )
 
 type application struct {
 	logger *slog.Logger
 	templateCache map[string]*template.Template
 	tier string
+	host string
 }
 
 func main() {
-	//Get env variables
-	addr := flag.String("addr", ":8080", "HTTP network address")
-	tier := flag.String("tier", "starter", "tier the core is on")
-	flag.Parse()
 	//Set up logger
 	logger := slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
 		AddSource: true,
 	}))
+	//Get env variables
+	tier := os.Getenv("TIER")
+	if len(tier) == 0 {
+		tier = "starter"
+	}
+	host := os.Getenv("HOST")
+	if len(host) == 0 {
+		logger.Error("Must specify host name.")
+		os.Exit(1)
+	}
 	//Set up template cache
 	templateCache, err := newTemplateCache()
 	if err != nil {
@@ -33,10 +39,11 @@ func main() {
 	app := application {
 		logger: logger,
 		templateCache: templateCache,
-		tier: *tier,
+		tier: tier,
+		host: host,
 	}
 
-	err = http.ListenAndServe(*addr, app.routes())
+	err = http.ListenAndServe(":8080", app.routes())
 	logger.Error(err.Error())
 	os.Exit(1)
 }
\ No newline at end of file