diff --git a/Environment-Variables.md b/Environment-Variables.md
index 2092c61..e7b67cf 100644
--- a/Environment-Variables.md
+++ b/Environment-Variables.md
@@ -11,6 +11,7 @@ This page will list all environment variables that could be passed into Statping
 - `CLEANUP_INTERVAL`          - Interval to check for old records (default 1 hour, '1h = 1 hour')
 - `ALLOW_REPORTS`             - Send Statping anonymous [error reports](https://sentry.io/) so we can see issues (default is false)
 - `SERVER_PORT`               - Port number to run Statping HTTP server on (or use -p/--port)
+- `READ_ONLY`                 - Run in a read only mode, this will not create, update, or delete records
 
 ### Automatic SSL Certificate
 With LetsEncrypt enabled, Statping will run through the SSL process and create the SSL certs in the `certs` folder. Read more about the SSL Process on the [SSL Wiki](https://github.com/statping/statping/wiki/SSL).