SSL/TLS Certificate Lookup
Check a domain's SSL/TLS certificate — who issued it, when it expires, and whether the chain is trusted
SSL/TLS Certificate for u-m.dev
Valid- Issued by (CA)
- Let's Encrypt
- Subject
- www.u-m.dev
- Valid from
- Sep 18, 2026
- Valid until
- Dec 17, 2026 (64 days remaining)
- Public key
- RSA 2048-bit
- Serial
- 05C13348F1378B8E1B8B20B6CF6E2E4680E9
- SHA-256 fingerprint
- AF:34:53:13:DF:27:98:6C:A6:10:CB:C4:0E:84:56:95:11:1E:77:94:74:34:76:6C:22:E4:75:A9:4C:15:22:7B
- Chain
- YR1 → Root YR → ISRG Root X1
Certificate Authority Authorization (CAA)
No CAA policy is published for this domain — any certificate authority may issue for it.
This certificate has been served since Sep 26, 2026.
Never get surprised by u-m.dev's certificate expiring
This is today's certificate. Turn on monitoring and we'll watch u-m.dev continuously, notifying you the moment anything moves across all three signals:
Uptime
We visit the site from multiple regions worldwide and email you within minutes if it goes down, with a per-region breakdown so a real outage stands out from a regional blip.
DNS changes
We watch NS, MX, CAA, DNSSEC, CNAME and A/AAAA records, and identify the host, network, and ASN behind them, so a real migration or hijack stands out from routine noise.
TLS certificate
We warn you 30, 14, 7, and 1 days before it expires, and flag it if the issuing authority changes or the certificate is unexpectedly replaced.
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