diff --git a/.envrc b/.envrc
index 3550a30..4ef3088 100644
--- a/.envrc
+++ b/.envrc
@@ -1 +1,8 @@
 use flake
+
+nix build nixpkgs#dbip-city-lite --no-link
+nix build nixpkgs#dbip-asn-lite --no-link
+
+export IP_CHECKER_CITY_DB=$(nix eval nixpkgs#dbip-city-lite.mmdb --raw)
+export IP_CHECKER_ASN_DB=$(nix eval nixpkgs#dbip-asn-lite.mmdb --raw)
+export IP_CHECKER_MODE=dev
diff --git a/main.go b/main.go
index efcbc3a..b69a1f0 100644
--- a/main.go
+++ b/main.go
@@ -22,16 +22,18 @@ var (
 )
 
 type ServerConfig struct {
-	Listen string
-	CityDB string
 	ASNDB  string
+	CityDB string
+	Listen string
+	Mode   string
 }
 
 func main() {
 	config = ServerConfig{
-		Listen: getEnvOr("IP_CHECKER_LISTEN", ":8080"),
-		CityDB: os.Getenv("IP_CHECKER_CITY_DB"),
 		ASNDB:  os.Getenv("IP_CHECKER_ASN_DB"),
+		CityDB: os.Getenv("IP_CHECKER_CITY_DB"),
+		Listen: getEnvOr("IP_CHECKER_LISTEN", ":8080"),
+		Mode:   os.Getenv("IP_CHECKER_MODE"),
 	}
 
 	if config.CityDB != "" {
@@ -135,6 +137,10 @@ func getIPCountry(ip string) string {
 
 func handleRequest(w http.ResponseWriter, r *http.Request) {
 	sourceIP := func() string {
+		if config.Mode == "dev" {
+			return "223.5.5.5"
+		}
+
 		if ip := r.Header.Get("X-Forwarded-For"); ip != "" {
 			return strings.Split(ip, ",")[0]
 		}