diff --git a/lib/web.go b/lib/web.go
index d2d225b..842cab3 100644
--- a/lib/web.go
+++ b/lib/web.go
@@ -54,6 +54,16 @@ func (f *Forgejo) handle(w http.ResponseWriter, r *http.Request) {
 	trySet(w.Header(), "Etag", info.ETag)
 	trySet(w.Header(), "Last-Modified", info.LastModified)
 	trySet(w.Header(), "Content-Length", info.Size)
+
+	if r.Header.Get("If-None-Match") == info.ETag {
+		w.WriteHeader(http.StatusNotModified)
+		return
+	}
+	if r.Header.Get("If-Modified-Since") == info.LastModified {
+		w.WriteHeader(http.StatusNotModified)
+		return
+	}
+
 	w.WriteHeader(http.StatusOK)
 	io.Copy(w, content)
 }