The following table includes information about the Certificate Transparency Logs that are recognized by Chromium. It includes information about who operates the log, the name the log has been given, and the URL that can be used for logging certificates or inspecting the certificates that have been logged.
Note: The authoritative list is maintained in the Chromium code base. This is merely informational.
| Log Name | Log URL | Log State | Log Spec | MMD | Temporal Interval Start | Temporal Interval End | Log Operator | Contact Info |
|---|---|---|---|---|---|---|---|---|
| Google ‘Argon2025h1’ log | https://ct.googleapis.com/logs/us1/argon2025h1/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2025-07-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Argon2025h2’ log | https://ct.googleapis.com/logs/us1/argon2025h2/ | Usable | RFC6962 | 86400 | 2025-07-01T00:00:00Z | 2026-01-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Argon2026h1’ log | https://ct.googleapis.com/logs/us1/argon2026h1/ | Usable | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2026-07-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Argon2026h2’ log | https://ct.googleapis.com/logs/us1/argon2026h2/ | Usable | RFC6962 | 86400 | 2026-07-01T00:00:00Z | 2027-01-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Xenon2025h1’ log | https://ct.googleapis.com/logs/eu1/xenon2025h1/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2025-07-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Xenon2025h2’ log | https://ct.googleapis.com/logs/eu1/xenon2025h2/ | Usable | RFC6962 | 86400 | 2025-07-01T00:00:00Z | 2026-01-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Xenon2026h1’ log | https://ct.googleapis.com/logs/eu1/xenon2026h1/ | Usable | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2026-07-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Google ‘Xenon2026h2’ log | https://ct.googleapis.com/logs/eu1/xenon2026h2/ | Usable | RFC6962 | 86400 | 2026-07-01T00:00:00Z | 2027-01-01T00:00:00Z | google-ct-logs@googlegroups.com | |
| Cloudflare ‘Nimbus2025’ | https://ct.cloudflare.com/logs/nimbus2025/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2026-01-01T00:00:00Z | Cloudflare | ct-logs@cloudflare.com |
| Cloudflare ‘Nimbus2026’ | https://ct.cloudflare.com/logs/nimbus2026/ | Qualified | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2027-01-01T00:00:00Z | Cloudflare | ct-logs@cloudflare.com |
| DigiCert Yeti2025 Log | https://yeti2025.ct.digicert.com/log/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2026-01-01T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert Nessie2025 Log | https://nessie2025.ct.digicert.com/log/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2026-01-01T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Wyvern2025h1’ Log | https://wyvern.ct.digicert.com/2025h1/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2025-07-07T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Wyvern2025h2’ Log | https://wyvern.ct.digicert.com/2025h2/ | Usable | RFC6962 | 86400 | 2025-07-01T00:00:00Z | 2026-01-07T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Wyvern2026h1’ | https://wyvern.ct.digicert.com/2026h1/ | Qualified | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2026-07-01T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Wyvern2026h2’ | https://wyvern.ct.digicert.com/2026h2/ | Qualified | RFC6962 | 86400 | 2026-07-01T00:00:00Z | 2027-01-01T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Sphinx2025h1’ Log | https://sphinx.ct.digicert.com/2025h1/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2025-07-07T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Sphinx2025h2’ Log | https://sphinx.ct.digicert.com/2025h2/ | Usable | RFC6962 | 86400 | 2025-07-01T00:00:00Z | 2026-01-07T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Sphinx2026h1’ | https://sphinx.ct.digicert.com/2026h1/ | Qualified | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2026-07-01T00:00:00Z | DigiCert | ctops@digicert.com |
| DigiCert ‘Sphinx2026h2’ | https://sphinx.ct.digicert.com/2026h2/ | Qualified | RFC6962 | 86400 | 2026-07-01T00:00:00Z | 2027-01-01T00:00:00Z | DigiCert | ctops@digicert.com |
| Sectigo ‘Sabre’ CT log | https://sabre.ct.comodo.com/ | ReadOnly | RFC6962 | 86400 | Sectigo | ctops@sectigo.com | ||
| Sectigo ‘Sabre2025h1’ | https://sabre2025h1.ct.sectigo.com/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2025-07-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Sabre2025h2’ | https://sabre2025h2.ct.sectigo.com/ | Usable | RFC6962 | 86400 | 2025-07-01T00:00:00Z | 2026-01-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Mammoth2025h1’ | https://mammoth2025h1.ct.sectigo.com/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2025-07-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Mammoth2025h2’ | https://mammoth2025h2.ct.sectigo.com/ | Usable | RFC6962 | 86400 | 2025-07-01T00:00:00Z | 2026-01-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Mammoth2026h1’ | https://mammoth2026h1.ct.sectigo.com/ | Qualified | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2026-07-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Mammoth2026h2’ | https://mammoth2026h2.ct.sectigo.com/ | Qualified | RFC6962 | 86400 | 2026-07-01T00:00:00Z | 2027-01-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Sabre2026h1’ | https://sabre2026h1.ct.sectigo.com/ | Qualified | RFC6962 | 86400 | 2026-01-01T00:00:00Z | 2026-07-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Sectigo ‘Sabre2026h2’ | https://sabre2026h2.ct.sectigo.com/ | Qualified | RFC6962 | 86400 | 2026-07-01T00:00:00Z | 2027-01-01T00:00:00Z | Sectigo | ctops@sectigo.com |
| Let’s Encrypt ‘Oak2025h1’ | https://oak.ct.letsencrypt.org/2025h1/ | Usable | RFC6962 | 86400 | 2024-12-20T00:00:00Z | 2025-07-20T00:00:00Z | Let’s Encrypt | sre@letsencrypt.org |
| Let’s Encrypt ‘Oak2025h2’ | https://oak.ct.letsencrypt.org/2025h2/ | Usable | RFC6962 | 86400 | 2025-06-20T00:00:00Z | 2026-01-20T00:00:00Z | Let’s Encrypt | sre@letsencrypt.org |
| Let’s Encrypt ‘Oak2026h1’ | https://oak.ct.letsencrypt.org/2026h1/ | Qualified | RFC6962 | 86400 | 2025-12-20T00:00:00Z | 2026-07-20T00:00:00Z | Let’s Encrypt | sre@letsencrypt.org |
| Let’s Encrypt ‘Oak2026h2’ | https://oak.ct.letsencrypt.org/2026h2/ | Qualified | RFC6962 | 86400 | 2026-06-20T00:00:00Z | 2027-01-20T00:00:00Z | Let’s Encrypt | sre@letsencrypt.org |
| TrustAsia Log2025a | https://ct2025-a.trustasia.com/log2025a/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2026-01-01T00:00:00Z | TrustAsia | trustasia-ct-logs@trustasia.com |
| TrustAsia Log2025b | https://ct2025-b.trustasia.com/log2025b/ | Usable | RFC6962 | 86400 | 2025-01-01T00:00:00Z | 2026-01-01T00:00:00Z | TrustAsia | trustasia-ct-logs@trustasia.com |
| TrustAsia ‘log2026a’ | https://ct2026-a.trustasia.com/log2026a/ | Usable | RFC6962 | 86400 | 2025-12-24T00:00:00Z | 2027-01-08T00:00:00Z | TrustAsia | trustasia-ct-logs@trustasia.com |
| TrustAsia ‘log2026b’ | https://ct2026-b.trustasia.com/log2026b/ | Usable | RFC6962 | 86400 | 2025-12-24T00:00:00Z | 2027-01-08T00:00:00Z | TrustAsia | trustasia-ct-logs@trustasia.com |