Add debugging notes.
diff --git a/README.md b/README.md
index eabde8c..4add38c 100644
--- a/README.md
+++ b/README.md
@@ -453,7 +453,20 @@
The following optional parameters are supported to filter the result set:
- `basepath` - base URI path for endpoints (default: `/`)
+## Debugging
+Setting an environment parameter (`NODE_DEBUG=request`) will dump the HTTP requests from the client library and responses received to `stderr`.
+
+```
+NODE_DEBUG=request node script.js
+```
+
+This parameter can also be set dynamically at runtime, provided this happens before the `openwhisk` module is required.
+
+```
+process.env.NODE_DEBUG='request';
+var openwhisk = require('openwhisk');
+```
## Development
