What powers 
undertow.io?
Last seen Dec 2025 · 7 technologies across 6 categories
Analytics
Caching
Varnish
since Feb 2022
CDN
Fastly
since Feb 2022
JavaScript libraries
Highlight.js
since Aug 2018
PaaS
GitHub Pages
since Feb 2022
UI frameworks
Bootstrap
since Feb 2021
AI Crawlers
No robots.txt, so all AI crawlers are allowed by default. Checked Sep 2026.
- robots.txt not found
- llms.txt not found
- ai.txt not found
AI Crawlers
No robots.txt, all AI crawlers allowed
Open Page Rank
5.97 / 10 · ranked #111,614 of all domains
149 referring domains · OpenPageRank
Infrastructure
- Hosted on Fastly (185.199.108.153)
- DNS: Hurricane Electric
- Email: no MX record returned
- SSL: Let's Encrypt, RSA 2048, expires Nov 2026
- Common Crawl link graph: rank 1,191,159, 3 hosts
DNS records as swept Sep 2026, certificate as seen Sep 2026. How the web is hosted