26th June 2020 - Link Blog
How CDNs Generate Certificates. Thomas Ptacek (now at Fly) describes in intricate detail the challenges faced by large-scale hosting providers that want to securely issue LetsEncrypt certificates for customer domains. Lots of detail here on the different ACME challenges supported by LetsEncrypt and why the new tls-alpn-01 challenge is the right option for operating at scale.
Recent articles
- GPT-5.4 mini and GPT-5.4 nano, which can describe 76,000 photos for $52 - 17th March 2026
- My fireside chat about agentic engineering at the Pragmatic Summit - 14th March 2026
- Perhaps not Boring Technology after all - 9th March 2026