← All website monitoring tools
Nmap
Standard network discovery + port/service scanner — universal first step for any audit.
Free tier: fully free, open-source
What it does well
- Extremely flexible scanning via the Nmap Scripting Engine (NSE) for custom tasks.
- Identifies host operating systems, services, and versions with high accuracy.
- Completely free and open-source, with decades of community testing and development.
Where it falls short
- Self-hosted and command-line only; requires technical expertise to install and operate.
- Lacks a built-in GUI, historical data storage, or automated alerting features.
- Scans can be slow and resource-intensive on large or complex networks.
Alternatives to Nmap
OWASP ZAP
freeMost popular free open-source DAST scanner — active/passive web scanning, intercepting proxy, CI/CD integration.
Pentest-Tools.com
freemiumOnline toolkit of 25+ pentest scanners (web, network, recon) — paid plans from $93/mo with unlimited scans.
Greenbone / OpenVAS
freemiumOpen-source vulnerability scanner descended from Nessus — free Community Edition, paid appliances for enterprise.
Template-driven fast scanner — community templates cover thousands of CVEs. Free CLI, paid managed cloud.