diff --git a/networking/filtering-proxy/README.md b/networking/filtering-proxy/README.md
index 3bd6476a..5df1d0ee 100644
--- a/networking/filtering-proxy/README.md
+++ b/networking/filtering-proxy/README.md
@@ -14,3 +14,23 @@ To simplify the usage of the proxy, a Cloud DNS private zone is created and the
You can optionally deploy the Squid server as [Managed Instance Group](https://cloud.google.com/compute/docs/instance-groups) by setting the `mig` option to `true`. This option defaults to `false` which results in a standalone VM.
![High-level diagram](squid.png "High-level diagram")
+
+
+## Variables
+
+| name | description | type | required | default |
+|---|---|:---: |:---:|:---:|
+| billing_account | Billing account id used as default for new projects. | string
| ✓ | |
+| prefix | Prefix used for resources that need unique names. | string
| ✓ | |
+| region | Default region for resources | string
| ✓ | |
+| root_node | Root node for the new hierarchy, either 'organizations/org_id' or 'folders/folder_id'. | string
| ✓ | |
+| *cidrs* | CIDR ranges for subnets | map(string)
| | ...
|
+| *mig* | Enables the creation of an autoscaling managed instance group of squid instances. | bool
| | false
|
+| *nat_logging* | Enables Cloud NAT logging if not null, value is one of 'ERRORS_ONLY', 'TRANSLATIONS_ONLY', 'ALL'. | string
| | ERRORS_ONLY
|
+
+## Outputs
+
+| name | description | sensitive |
+|---|---|:---:|
+| squid-address | None | |
+