crt.sh Alternatives: Certificate Transparency Search
crt.sh (Sectigo) has been the standard public Certificate Transparency log search since 2013. Finds every certificate issued for a domain, surfaces subdomain enumeration vectors. Pain points: frequent overload, raw UI, undocumented API rate limits, RU clients hit TLS issues. Alternatives: Enterno.io Subdomain Enumeration, CertSpotter (SSLMate), crt-search.io, Google Transparency Report.
Below: competitor overview, feature-by-feature comparison, when Enterno.io wins, FAQ.
About the Competitor
crt.sh launched by Sectigo (ex-Comodo CA) in 2013. Free, no signup, SQL-like query syntax. Indexes CT logs from Google, Cloudflare, Let's Encrypt, Sectigo. In 2024-2026 often unreachable from Russia without VPN; response time 3-30 s.
Enterno.io vs Competitor — Feature Comparison
| Feature | Enterno.io | Competitor |
|---|---|---|
| Free CT-log search | ✅ | ✅ |
| Subdomain enumeration | ✅ | ⚠️ Manual |
| No-key API | ⚠️ Pro | ✅ |
| RU reachability | ✅ | ⚠️ |
| Response time | 1-2 s | 3-30 s |
| Active certs filter | ✅ | ⚠️ manual |
| SSL chain validation | ✅ | ❌ |
| Integrated SSL checker | ✅ | ❌ |
When to Pick Enterno.io
- You need quick access from Russia without VPN
- You care about active/expired + SSL-chain validity, not just a list
- You want subdomain enumeration + SSL checker in one flow
- If you need raw SQL queries against CT logs — crt.sh still wins
Why teams trust us
How it works
Enter domain
TLS chain verified
Expiry date & vulnerabilities
What Does the SSL Check Cover?
SSL/TLS is the encryption protocol that protects data between the browser and server. Our tool analyzes the certificate, chain of trust, TLS version, and knownvulnerabilities.
Certificate Details
Issuer, validity period, signature algorithm, covered domains (SAN), and validation type (DV/OV/EV).
Chain of Trust
Full chain verification: from leaf certificate through intermediates to root CA.
TLS Analysis
Protocol version (TLS 1.2/1.3), cipher suites, Perfect Forward Secrecy (PFS) support.
Expiry Alerts
Set up a monitor — get Telegram and email alerts 30/14/7 days before expiration.
DV vs OV vs EV Certificates
- Confirms domain ownership only
- Issued in minutes automatically
- Free via Let's Encrypt
- Suitable for most websites
- Most common certificate type
- Organization (OV) or Extended Validation (EV)
- Issued in 1-5 business days
- Costs $50 to $500/year
- For finance, e-commerce, government sites
- Increases user trust
Who uses this
DevOps
SSL certificate monitoring
Security
TLS config audit
SEO
HTTPS as ranking factor
E-commerce
customer trust
Common Mistakes
www and subdomains.Best Practices
Strict-Transport-Security header forces browsers to always use HTTPS.Get more with a free account
SSL certificate monitoring, check history and alerts 30 days before expiry.
Sign up freeLearn more
How-to
Frequently Asked Questions
What is Certificate Transparency?
A public append-only log of every SSL certificate issued by public CAs. Chrome since 2018 requires each cert to be in a CT log for trust.
Can I find hidden subdomains?
Yes, CT logs surface every certificate including for *.internal.example.com. A well-known recon vector for security testing.
Does crt.sh have an API?
Technically yes (output=json) but undocumented and unknown rate limits. Enterno.io — public API with a declared limit.
How is it different from DNS?
DNS shows only active A/CNAME. CT logs cover every cert ever issued, even retired. Deeper.