diff --git a/Dockerfile b/Dockerfile
index 00efb91..20c5649 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,6 +3,7 @@ ARG GOPROXY_URL=https://gitea.nehmer.net/api/packages/torben/go,https://proxy.go
 
 FROM golang:${GO_VERSION}-bookworm AS build
 WORKDIR /src
+ARG GOPROXY_URL
 ENV GOPROXY=${GOPROXY_URL}
 
 COPY go.mod ./