Crt.sh Search
Free online crt.sh and Certificate Transparency search tool. Discover subdomains, audit SSL/TLS certificates, and export hostnames with multi-source fallback.
How to Use Crt.sh Search
Open the Crt.sh Search tool on toollabs.in.
Enter the domain, IP address, or network parameter you want to analyze.
The tool generates the appropriate command or queries the relevant DNS/network service.
Review the results including technical details, response data, and suggested next steps for troubleshooting.
Why Use Crt.sh Search?
Crt.sh Search on toollabs.in is designed for quick network diagnostics. Diagnostic requests are processed statelessly in-memory and queries are never logged, tracked, or stored on our servers.
Designed for developers, system administrators, and security practitioners, Crt.sh Search streamlines common inspection, diagnostic, and syntax generation workflows directly in your browser.
Built with modern web standards and responsive layouts, Crt.sh Search runs smoothly across desktop and mobile devices without requiring extra plugins or software installation.
100% Free
No subscriptions, no paywalls, no hidden costs
Privacy First
All processing happens in your browser
Lightning Fast
No server latency, instant results
No Signup
Start using immediately, no account needed
Frequently Asked Questions
What is crt.sh and Certificate Transparency?▼
Certificate Transparency (CT) is an open framework of public, append-only logs where Certificate Authorities must log every issued SSL/TLS certificate. crt.sh is a public web interface and PostgreSQL database operated by Sectigo that indexes these transparency logs.
Why does crt.sh sometimes fail or return 502 Bad Gateway?▼
The public crt.sh database frequently experiences heavy load, locking contention, and query timeouts on large wildcard searches. ToolLabs includes automated multi-source failover (CertSpotter and passive DNS caches) so searches succeed even when crt.sh is under heavy load.
Can CT logs reveal unlinked or hidden subdomains?▼
Yes. Whenever a web team provisions an SSL certificate for an internal portal, API endpoint, or staging server (e.g. dev.example.com, staging.api.example.com), the certificate name is permanently recorded in public CT logs, making it visible even if the subdomain has no public inbound links.
Does searching a domain alert the target or violate privacy?▼
No. Searching Certificate Transparency logs is completely passive. It queries public historical log databases and does not send packets or HTTP requests to the target domain's servers.
Use Cases
Subdomain Enumeration
Discover subdomains and attack surfaces during authorized security assessments
Certificate Auditing
Verify active, expiring, and historic SSL/TLS certificates issued for your company domains
Shadow IT Discovery
Uncover forgotten dev, QA, or third-party SaaS subdomains provisioned with certificates
Examples
Search Domain
Input:
example.com
Output:
Discovered subdomains and active certificates
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