cnames vs crt.sh: Side-by-Side Comparison (2026)
Features, pricing, ratings, and pros & cons — compared head-to-head.
cnames is a free external attack surface management tool. crt.sh 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 managing large subdomain inventories who need to quickly identify third-party service dependencies will find cnames valuable for that single, unglamorous job. The tool does one thing well: bulk CNAME resolution at no cost, which means you can run it repeatedly without justifying recurring spend to procurement. This is a CLI utility, not a platform; it won't replace your external attack surface management tool, but it will save time in the reconnaissance phase before you feed results into one.
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.
