crt.sh vs Sublist3r: Side-by-Side Comparison (2026)
Features, pricing, ratings, and pros & cons — compared head-to-head.
crt.sh is a free external attack surface management tool. Sublist3r 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 NIST CSF 2.0 coverage, core features, integrations, company size fit, here is our conclusion:
Security teams doing threat intelligence or domain monitoring should use crt.sh as a free, fast way to spot certificate issuance anomalies that signal domain takeover or phishing campaigns before they scale. Certificate Transparency logs index roughly 15 billion certificates, giving you real-time visibility into what's been legitimately issued against your domains and competitors' infrastructure. Skip this if you need automated alerting or integration into your SIEM; crt.sh is a lookup tool, not a monitoring platform, and catching malicious certificates requires manual checks or custom scripting.
Penetration testers and bug bounty hunters running initial reconnaissance need Sublist3r because it aggregates subdomain enumeration across multiple OSINT sources and search engines in a single Python script, cutting research time on scope mapping. The tool has 10,855 GitHub stars and requires no API keys or paid subscriptions, making it accessible for individual practitioners and small teams. Skip this if your workflow depends on real-time passive DNS feeds or if you need a GUI; Sublist3r is CLI-only and relies on search engine indexing lag, so it won't catch freshly provisioned infrastructure.
