Wallarm API Firewall is a free light-weighted API Firewall that protects your API endpoints in cloud-native environments with API schema validation. Wallarm API Firewall relies on a positive security model allowing calls that match a predefined API specification, while rejecting everything else. Wallarm API Firewall is available as a Docker container (with 15M+ pulls to

https://lab.wallarm.com/wallarm-api-firewall-outperforms-nginx-in-a-production-environment/