diff --git a/build-and-tag.sh b/build-and-tag.sh
index a7caad7..823fb3a 100755
--- a/build-and-tag.sh
+++ b/build-and-tag.sh
@@ -1,13 +1,28 @@
 #!/usr/bin/env bash
 # Build the container image and tag it for the registry.
-# Usage: ./build-and-tag.sh <tag>   e.g. ./build-and-tag.sh v1
+# Usage: ./build-and-tag.sh            # reads version.txt, increments, builds, pushes
+# Usage: ./build-and-tag.sh <tag>      # explicit tag (e.g. ./build-and-tag.sh v6)
 set -e
 
 IMAGE=hardings-service
 REGISTRY=registry.digitalsorcery.net
-TAG="${1:?usage: $0 <tag>}"
+VERSION_FILE="$(dirname "$0")/version.txt"
 
+if [ -n "$1" ]; then
+  TAG="$1"
+else
+  # Read current version, increment the numeric portion
+  CURRENT=$(cat "$VERSION_FILE" | tr -d '[:space:]')
+  NUM=$(echo "$CURRENT" | sed 's/v//')
+  TAG="v$((NUM + 1))"
+fi
+
+echo "Building ${IMAGE}:${TAG} ..."
 podman build -t "${IMAGE}:${TAG}" -f Containerfile .
 podman tag "${IMAGE}:${TAG}" "${REGISTRY}/${IMAGE}:${TAG}"
+podman push "${REGISTRY}/${IMAGE}:${TAG}"
 
-echo "Push with: podman push ${REGISTRY}/${IMAGE}:${TAG}"
+# Update version.txt to match the tag we just pushed
+echo "$TAG" > "$VERSION_FILE"
+
+echo "Done. ${REGISTRY}/${IMAGE}:${TAG} pushed."
diff --git a/version.txt b/version.txt
new file mode 100644
index 0000000..9c0be88
--- /dev/null
+++ b/version.txt
@@ -0,0 +1 @@
+v6