diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..cb570c8
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,12 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [0.3.0] - 2021-07-31
+### Changed
+- Changed the default base URL for the sandbox environment to match https://shipping.pitneybowes.com/overview.html#sandbox-environment
+- Changed the way OAuth tokens are cached so that they vary by environment.
\ No newline at end of file