crt.sh vs Subra: 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. Subra 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.
Security teams running manual subdomain discovery workflows or evaluating attack surface management on a budget should start with Subra; it wraps the open-source subfinder tool in a web interface that cuts the friction of command-line enumeration without requiring infrastructure spend. The 54 GitHub stars and free pricing model mean you can validate subdomain coverage gaps in minutes, not weeks of vendor evaluation. Skip this if you need continuous monitoring, prioritization scoring, or integration with your existing vulnerability management stack; Subra is a one-time discovery tool, not a platform.
