ctlogs.dev is an independent Certificate Transparency search engine: the same kind of certificate lookups crt.sh serves, over an index of billions of certificates, built to stay fast under load.
crt.sh appears to be down right now — run your search here instead:
If a monitoring script or CI job just failed because crt.sh timed out, the query interface here is deliberately close: the same ?q= parameter, the same *.example.com wildcard style, the same &output=json switch.
# before
curl 'https://crt.sh/?q=example.com&output=json'
# after
curl 'https://ctlogs.dev/search?q=example.com&output=json'The response is a JSON array too, with cleaner field names (not_before, not_after, serial_hex, issuer, …) — a one-line change to most scripts, not a parser rewrite. Anonymous requests are rate-limited per IP; for sustained or keyed access use the REST API.
| crt.sh | ctlogs.dev | |
|---|---|---|
| Domain search | yes | yes |
Wildcard suffix search (*.example.com) | yes | yes |
| Organization search | yes | yes — exact and substring |
| Serial number | yes | yes |
| SHA-256 fingerprint | yes | yes |
JSON output (&output=json) | yes | yes — different field names |
| Log coverage | all CT logs | 64 logs, 52.87B entries ingested (live coverage) |
| Raw DER/PEM download | yes | no |
| Public SQL interface | yes | no |
| RSS feeds | yes | no |
30 days agotoday
Uptime last 24 hours: 76.13% · last 30 days: 25.79% · most recent outage: Sep 6, 03:22 UTC, lasted ~2 min
We check crt.sh once a minute with a real certificate query (not just a page load), from an independent network. Rate-limited responses are counted as unknown, not as downtime.
See the live badge at the top of this page — it reflects a real query issued within the last minute. If crt.sh is down, search the certificate transparency record here in the meantime.
crt.sh is a free service backed by a shared PostgreSQL cluster, and heavy queries from many users routinely saturate it. The front page can load fine while queries time out — which is why our checker issues a real query.
output=json?Yes — append &output=json to any search, or use the keyed REST API for sustained access.
The same place crt.sh's does: the public Certificate Transparency logs. We continuously ingest every browser-trusted log — see monitored logs for per-log coverage and freshness.
crt.sh is a service operated by Sectigo Limited. ctlogs.dev is an independent service and is not affiliated with or endorsed by Sectigo.