diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..2eee393
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module github.com/ttacon/libphonenumber
+
+go 1.15
+
+require (
+	github.com/golang/protobuf v1.0.0
+	github.com/ttacon/builder v0.0.0-20170518171403-c099f663e1c2
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..0b26dd6
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,4 @@
+github.com/golang/protobuf v1.0.0 h1:lsek0oXi8iFE9L+EXARyHIjU5rlWIhhTkjDz3vHhWWQ=
+github.com/golang/protobuf v1.0.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/ttacon/builder v0.0.0-20170518171403-c099f663e1c2 h1:5u+EJUQiosu3JFX0XS0qTf5FznsMOzTjGqavBGuCbo0=
+github.com/ttacon/builder v0.0.0-20170518171403-c099f663e1c2/go.mod h1:4kyMkleCiLkgY6z8gK5BkI01ChBtxR0ro3I1ZDcGM3w=