diff --git a/build/git.sh b/build/git.sh
new file mode 100644
index 0000000..464114b
--- /dev/null
+++ b/build/git.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+
+# Check current branch
+if test "master" != "$(git symbolic-ref --short HEAD)"; then
+  echo 'Not on `master` branch.' >&2;
+  exit 128;
+fi
+
+
+# Check local working tree
+if test -n "$(git status --porcelain)"; then
+  echo 'Unclean working tree. Commit or stash changes first.' >&2;
+  exit 128;
+fi
+
+# Check remote history
+if test "0" != "$(git rev-list --count --left-only @'{u}'...HEAD)"; then
+  echo 'Remote history differ. Please pull changes.' >&2;
+  exit 128;
+fi
diff --git a/package.json b/package.json
index bd49025..625d42a 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,7 @@
     "version": "conventional-changelog -p angular -i CHANGELOG.md -s && git add CHANGELOG.md",
     "test:push": "jest --coverage --coverageReporters=text-lcov | coveralls",
     "test": "jest",
-    "release": "bash build/release.sh"
+    "release": "bash build/git.sh && bash build/release.sh"
   },
   "repository": {
     "type": "git",