diff --git a/Makefile b/Makefile
index 69a64f0..46502b0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,24 @@
 .PHONY: deploy
 
+VNU_RELEASE=20.6.30
+VNU_URL=https://github.com/validator/validator/releases/download/$(VNU_RELEASE)/vnu.jar_$(VNU_RELEASE).zip
+
 deploy:
 	rm -rf deploy
 	hyde gen
 	#hyde publish
 
+vnu.jar_$(VNU_RELEASE).zip:
+	wget $(VNU_URL)
+
+vnu.jar: vnu.jar_$(VNU_RELEASE).zip
+	unzip -p $< dist/vnu.jar > $@ || (rm "$@"; false)
+
+.PHONY:
+validate: vnu.jar
+	hyde gen
+	java -jar vnu.jar --skip-non-html --also-check-css --also-check-svg --stdout deploy | egrep -v 'Section lacks heading|Article lacks heading|Consider using the “h1” element as a top-level heading only'
+
 .PHONY: update-tufte-css
 update-tufte-css:
 	git subtree pull -P tufte-css --squash https://github.com/edwardtufte/tufte-css.git gh-pages