GRASSMARLIN vs Nautilus OT: Side-by-Side Comparison (2026)
Features, pricing, ratings, and pros and cons, compared head to head.
GRASSMARLIN is a free ot asset discovery tool. Nautilus OT is a commercial ot asset discovery tool by Nautilus. Compare features, ratings, integrations, and community reviews side by side to find the best ot asset discovery fit for your security stack. Independent and vendor-neutral: our scores and rankings are earned, never bought — sponsored placement is always labeled.
CST VerdictBased on our analysis of core features, here is our conclusion:
Operations teams defending critical infrastructure without dedicated ICS/SCADA visibility should start with GRASSMARLIN; its passive network mapping gives you topology sight-lines without touching production systems, which matters when downtime costs six figures per hour. The tool is free and runs on commodity hardware, so deployment friction is nearly zero for teams of any size. The tradeoff is real: GRASSMARLIN maps what exists but doesn't actively hunt for misconfigurations or lateral movement, so it's a foundation layer, not a standalone defense.
Data verified Sep 2026
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