Certificate Transparency search tool
crt.sh (crt.sh) scores 58 out of 100 on Brand Analyzer, placing it in the Developing tier among Technology brands, SaaS brands, in the 6th percentile of 50337 Technology brands.
crt.sh is a free, web-based certificate search service that allows users to search and monitor Certificate Transparency (CT) logs for SSL/TLS certificates. Founded in 2015 and owned by Sectigo, it serves as a public resource for tracking certificate issuance across domains. The platform is primarily used by security researchers, system administrators, and developers who need to audit and verify certificate issuance for security and compliance purposes.
| Brand Name | crt.sh |
|---|---|
| Domain | crt.sh |
| Industry | Technology, SaaS |
| Founded | 2015 |
| Parent Company / Owner | Sectigo |
| Main Competitors | Censys (93/100), SSLMate CertSpotter (71/100), Shodan (91/100), Google Certificate Transparency, Merklemap |
Moz Domain Authority 54/100 vs category average 39 / leader 100 - a strong backlink profile, so AI systems frequently encounter mentions of the brand.
Ranked #32,479 on the Tranco list of most-visited sites - strong traffic reinforces the brand's prominence to AI models.
crt.sh has a dedicated Wikipedia entity - a top-weighted signal AI models rely on to identify and describe the brand.
The homepage meta description reads "To provide a free and accessible way to search and monitor Certificate Transparency logs for SSL/TLS certificates." (No meta description) - this is the summary AI engines are most likely to quote.
Structured data on the homepage: No structured data or Open Graph tags detected. Adding Organization and FAQ schema would further help AI crawlers parse the brand's identity.
AI-crawler access: No robots.txt found (default: all bots allowed, but explicit file preferred) - robots.txt controls whether engines like GPTBot and ClaudeBot can read the site at all.
Detected tech stack: Nginx.
Social footprint: verified profiles on X (Twitter), LinkedIn, Instagram, GitHub; no detected presence on Facebook, YouTube - consistent profiles reinforce the brand's identity across the web.
0 Reddit mentions - community discussion signals real-world reputation to AI models.
Live results from asking a general-purpose AI assistant about the brand, checked October 2026.
When asked "What is crt.sh?", Claude could identify the brand as of October 2026. crt.sh is a free certificate transparency log search tool run by Sectigo, allowing users to look up SSL/TLS certificates issued for a given domain by querying public Certificate Transparency logs. Best known for Searching Certificate Transparency logs to find SSL certificates issued for a domain.
When asked "Best brands similar to crt.sh?", Claude would recommend crt.sh as of October 2026. It's a widely used go-to tool among security researchers and sysadmins for certificate transparency lookups and subdomain enumeration.
Common questions people ask in Google, ChatGPT, Claude, Gemini, Perplexity, and other AI search engines.
crt.sh's main competitors in Technology: Censys (93/100), SSLMate CertSpotter (71/100), Shodan (91/100).
Sources: Brand Analyzer scan
crt.sh offers a free web-based search and monitoring interface for Certificate Transparency logs. Its core service allows users to query SSL/TLS certificate data by domain name, organization, certificate authority, or other identifiers, returning details such as issuance dates, certificate chains, and log entries. It does not sell commercial products but provides this search functionality as a public utility.
Sources: crt.sh official site
crt.sh is a free, web-based certificate search service that enables users to search and monitor Certificate Transparency (CT) logs for SSL/TLS certificates. It was founded in 2015 and is owned by Sectigo, a certificate authority. The service provides a public interface for querying CT log data, which records the issuance of digital certificates across the internet.
Sources: crt.sh official site
crt.sh has limited AI-search visibility, scoring 45/100 on Brand Analyzer's AI visibility composite (visibility 65, trust 19, recommendation 40). This estimates how likely AI engines like ChatGPT, Claude, Gemini and Perplexity are to know, trust, and recommend the brand.
Sources: crt.sh official site
crt.sh was founded in 2015. crt.sh operates in the Technology category. It is analyzed by Brand Analyzer across seven brand dimensions and AI-search visibility.
Sources: Wikidata
crt.sh allows users to search Certificate Transparency logs to find SSL/TLS certificates issued for specific domains, organizations, or certificate authorities. It provides tools to monitor certificate issuance over time, helping identify newly issued, expired, or potentially unauthorized certificates. Users can query by domain name, certificate fingerprint, or other identifiers to retrieve detailed certificate metadata sourced directly from public CT logs.
Sources: crt.sh official site
crt.sh scores 40/100 on Brand Analyzer's AI recommendation signal, indicating it is less likely to be surfaced when AI assistants like ChatGPT suggest Technology options. Recommendation depends on crawlability, structured data, and category authority; a Wikipedia presence helps.
Sources: crt.sh official site
crt.sh can improve AI discoverability by strengthening structured data (Organization and FAQ schema), maintaining an accurate Wikipedia/Wikidata entity, earning authoritative citations, and keeping content crawlable for AI bots. Brand Analyzer measures these as visibility, trust, and recommendation signals.
Sources: crt.sh official site
crt.sh is used by security researchers, system administrators, and developers who need to monitor and verify SSL/TLS certificate issuance for domains they manage or investigate. It is commonly used in security audits, domain reconnaissance, and incident response to check for certificates issued without authorization or to track certificate history and renewal.
Sources: crt.sh official site
crt.sh is owned by or part of Sectigo. crt.sh operates in the Technology category.
Sources: Wikidata
crt.sh is known for being one of the most widely used public interfaces into Certificate Transparency log data, allowing anyone to search for SSL/TLS certificates issued for a given domain. It is frequently referenced in security research, penetration testing, and domain reconnaissance as a quick way to enumerate subdomains and certificate history.
Sources: crt.sh official site
crt.sh is popular because it offers a free, straightforward way to search Certificate Transparency logs, which are otherwise large and complex datasets. Security professionals, developers, and researchers use it to quickly look up certificates for a domain, discover subdomains, and monitor for unauthorized or unexpected certificate issuance, making it a convenient and accessible tool for both routine administration and security investigations.
Sources: crt.sh official site
crt.sh scores 45/100 for AI visibility - how well ChatGPT, Claude, Perplexity and Google AI Overviews can discover, identify and cite the brand.
crt.sh has a limited AI-visibility profile at 45/100 - a proxy for how readily ChatGPT, Perplexity and Google's AI Overviews can recognise and cite it. Its strongest area is visibility (65/100) and its weakest is trust (19/100). It benefits from a recognised Wikipedia company entity, a Wikidata knowledge-graph entry and a global traffic rank of #32,479 (Tranco). The main gaps holding it back: thin schema.org structured data and no llms.txt to steer AI to its best pages. In a live check, Claude could already identify crt.sh from memory (October 2026) - a sign these signals are paying off.
The score combines seven dimensions - name quality, digital presence, visual identity, messaging clarity, trust foundation, AI discoverability, and brand authority - into a single objective benchmark.
Ranked closest to crt.sh: Crowdtech (58/100), Covinsys (58/100), Cybba (58/100), Dahrkael (58/100).
A step up - brands to learn from: Zypp Electric (71/100), 作业帮 (Zuoyebang) (71/100).
Category leader: Hostinger (97/100).
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