crt.sh Alternatives: Certificate Transparency Search

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.

• 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

For those seeking alternatives to crt.sh for Certificate Transparency (CT) monitoring in 2026, options include Google's Certificate Transparency Log, Digicert's Certificate Transparency, and Cloudflare's transparency logs. Each service offers unique features, such as real-time monitoring, enhanced security measures, and integration capabilities, aiding in the management of SSL/TLS certificates effectively.

When evaluating alternatives to crt.sh, it's essential to consider the specific features that each service offers. Here are some of the key features to look for:

• Real-Time Monitoring: The ability to receive immediate alerts on new certificates issued for your domain.
• Search Capabilities: Advanced searching options, including wildcard support and filtering by issuer or domain.
• Integration with Other Tools: Compatibility with existing infrastructure monitoring tools (e.g., Grafana, New Relic).
• Compliance and Audit Support: Features that help in maintaining compliance with standards like RFC 6962.

For example, Google's Certificate Transparency Log allows users to query logs via their API, providing a seamless way to integrate CT data into existing workflows. Using the following command, you can check for certificates associated with a specific domain:

curl -X GET 'https://ct.googleapis.com/logs/argon2021/ct/v1/get-entries?start=0&end=100'

This command retrieves the first 100 entries from the Argon 2021 log, allowing users to analyze certificate issuance trends effectively.

To help you make an informed decision, here’s a comparative analysis of some prominent crt.sh alternatives available in 2026:

Google's CT Log is known for its robust API, allowing users to access logged certificates programmatically. Digicert’s offering, while paid, provides extensive support for enterprises with compliance needs, making it a preferred choice for larger organizations. Cloudflare’s CT log provides a free solution with decent integration capabilities, particularly for users already in the Cloudflare ecosystem.

To leverage these alternatives effectively, organizations should evaluate their specific requirements, such as the need for real-time alerts, historical data access, and integration with monitoring tools, to select the most fitting service.