diff --git a/README.md b/README.md
index d2c7486..feb0a9a 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,10 @@ The following settings are available for configuration via environment variables
 - ``TAILSCALE_SHIELDS_UP"`` - Block incoming connections from other devices on your Tailscale 
   network. Useful for personal devices that only make outgoing connections. Defaults to off.
 - ``TAILSCALED_VERBOSE`` - Controls verbosity for the tailscaled command. Defaults to 0.
+- ``TAILSCALE_TIMEOUT`` - Maximum amount of time to wait for the Tailscale service to initialize.
+  The duration can be any value parseable by time.ParseDuration(). Defaults to 0s, which blocks
+  forever. Heroku will timeout after its boot timeout is reached (60s by default) and the dyno
+  will crash if the value of this variable is greater.
 
 The following settings are for the compile process for the buildpack. If you change these, you must
 trigger a new build to see the change. Simply changing the environment variables in Heroku will not