What powers primer3.org?
Last seen Oct 2026 · 4 technologies across 3 categories
Caching
Varnish
since Apr 2022
CDN
Fastly
since Apr 2022
PaaS
GitHub Pages
since Apr 2022
Strato
since Nov 2022
AI Crawlers
Doesn't mention any of the 33 AI crawlers we track in its robots.txt; all are allowed by default. Checked Oct 2026.
- robots.txt found
- llms.txt not found
- ai.txt not found
AI Crawlers
No AI crawlers blocked
Audience
- 90% desktop
- 10% phone
India
Japan
United States
South Korea
Where the site's Chrome visitors come from, largest estimated audience first.
Open Page Rank
2.81 / 10 · ranked #1,950,534 of all domains
17 referring domains · OpenPageRank
Core Web Vitals
| LCP | 0.9 s |
| CLS | 0 |
| TTFB | 500 ms |
Real user p75, Chrome UX Report, Sep 2026.
Page
- Language: English
- CDN: Fastly
- Weight: 0.0 MB · 3 requests
Homepage as crawled by the HTTP Archive, Oct 2026.
Infrastructure
- Hosted on Fastly (185.199.108.153)
- DNS: STRATO
- Email: STRATO
- Email security: no SPF record, DMARC reject
- SSL: Let's Encrypt, RSA 2048, expires Nov 2026
- Common Crawl link graph: rank 574,443, 2 hosts
DNS records as swept Oct 2026, certificate as seen Oct 2026. How the web is hosted