I got a call from a small business owner on a Monday morning.
His website had been showing "Your connection is not secure" since Friday. He'd lost a full weekend of enquiries. The SSL certificate had expired — quietly, automatically — and nobody had noticed.
Auto-renewal had failed silently. No alert. No email. Just customers seeing a red warning screen and leaving.
I built a bulk SSL certificate monitor. Give it any list of domains, it connects directly, reads the certificate, and tells you exactly how many days you have left.
I ran it against 12 major UK websites this week:
→ 11 valid — all currently healthy
→ Shortest expiry: barclays.co.uk at 40 days — they run on short renewal cycles
→ 1 domain throwing a certificate verification error (companieshouse.gov.uk)
→ The smallest window I've seen on a client's site: 14 days before it would have gone dark
The big sites automate it properly and have teams watching. Small businesses are the ones that get caught out — often because they're relying on their hosting provider to handle it and don't realise when it stops working.
Zero external dependencies. Just Python's ssl and socket libraries. Runs in 15 seconds against any list of domains.
The Monday morning call was the reason I built it.
Interested in this project?
I'm always happy to talk through how it was built, the problems it solves, or how something similar could work for you.