diff --git a/package.json b/package.json
index 0df8d79..2908a39 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,7 @@
   },
   "homepage": "https://github.com/ipld/js-ipld-bitcoin#readme",
   "dependencies": {
+    "async": "^2.6.1",
     "bitcoinjs-lib": "^3.3.2",
     "cids": "~0.5.2",
     "git-validate": "^2.2.2",