crt.sh vs S3BucketList: 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. S3BucketList 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 hunting for exposed S3 buckets during reconnaissance will find S3BucketList useful for its passive discovery approach; the Chrome extension catches bucket references embedded in web traffic that traditional scanners miss entirely. With 124 GitHub stars and zero setup friction, it's practical for small AppSec or cloud security teams that need quick surface-level visibility without deploying infrastructure. Skip this if you need automated continuous monitoring or remediation workflows; S3BucketList is a lightweight reconnaissance aid, not a replacement for cloud posture management tools.
