Knock vs Amass: 2026 Comparison
Knock is a free external attack surface management tool. Amass is a free external attack surface management tool. Compare features, ratings, integrations, and community reviews side by side to find the best external attack surface management fit for your security stack.
CST VerdictBased on our analysis of available product data, here is our conclusion:
Security teams doing external attack surface reconnaissance on a budget should start with Knock; it's free, it works, and the 4,054 GitHub stars reflect actual adoption rather than marketing hype. The tool excels at the narrow job of subdomain enumeration, which maps NIST Govern and Identify functions by forcing you to know what's actually exposed before you can defend it. Skip Knock if you need continuous monitoring or API integration into your existing ASM stack; this is a point-in-time scanner you run manually, not a platform that feeds ongoing discovery into your risk register.
Security teams building reconnaissance automation into their reconnaissance workflow should start with Amass because it outperforms commercial tools at subdomain enumeration speed and catches assets that paid solutions miss through its multi-source passive collection approach. The 14,260 GitHub stars reflect sustained adoption by practitioners who've validated it against their own external asset inventories. Skip this if you need managed threat intelligence feeds, API-based asset tagging, or risk scoring; Amass is a discovery engine, not an asset management platform.
