diff --git a/README.md b/README.md
index c3da780..cab3ebc 100644
--- a/README.md
+++ b/README.md
@@ -107,6 +107,19 @@ Subfinder will work after using the installation instructions however to configu
 - [Passivetotal](http://passivetotal.org/)
 - [SecurityTrails](http://securitytrails.com/)
 - [Censys](https://censys.io)
+- [Riddler](https://riddler.io)
+
+These are the configuration options you have to specify via the command line.
+```bash
+VirustotalAPIKey 
+PassivetotalUsername 
+PassivetotalKey
+SecurityTrailsKey
+RiddlerEmail
+RiddlerPassword
+CensysUsername
+CensysSecret
+```
 
 Theses values are stored in the $HOME/.config/subfinder/config.json file which will be created when you run the tool for the first time. To configure the services to use an API key, you need to use the tool with --set-config option which will allow you to set a configuration option. For example:
 
@@ -119,7 +132,7 @@ If you are using docker, you need to first create your directory structure holdi
 ```bash
 mkdir $HOME/.config/subfinder
 cp config.json $HOME/.config/subfinder/config.json
-nano $HOME/.config/subfinder/config.json (optional)
+nano $HOME/.config/subfinder/config.json
 ```
 After that, you can pass it as a volume using the following sample command.
 ```bash