The Cyber Swiss Army Knife - a web app for encryption, encoding, compression and data analysis. Built and maintained by GCHQ (The UK intelligence and security organisation).

Unifying API testing, API Performance testing, API Mocks and UI testing.

Nuclei security scanning and automation platform

Automated robustness testing at the UI level

Checks web UI for browser compatibility (Compliance with Can I Use?)

Snort is the foremost Open Source Intrusion Prevention System (IPS) in the world. Snort IPS uses a series of rules that help define malicious network activity and uses those rules to find packets that match against them and generates alerts for users.