Domain report
fftw.org
fftw.org ranks in the top 0.016% of domains by connectivity (Common Crawl, cc-main-2026-jul-aug-sep), with 3 distinct hosts observed under it.
Connectivity
#20,773harmonic-centrality rank
- Top percentile
- 0.016%
- Hosts observed
- 3
From the Common Crawl cc-main-2026-jul-aug-sep hyperlink graph, 133,241,980 domains total. What this rank means
HTTPS reachability
200HTTP status
https://fftw.org/ answered with HTTP 200.
DNS records
- A
- 216.137.187.110
- AAAA
- No records found.
- MX
- 10 fftw.org.
- NS
- ns.fftw.org.
- ns2.afraid.org.
- puck.nether.net.
Live preview
This is a live, sandboxed embed of fftw.org — not a copy. What it shows can change any time the site itself does.
Domain registration (WHOIS / RDAP)
RDAP lookup failed (HTTP 429).
SSL certificate
Certificate Transparency lookup failed (HTTP 429).
HTTP & security headers
Response
- Server
- cloudflare
- Content-Type
- text/html
- Cache-Control
- Not sent
- Content-Encoding
- Not sent
Security
- Content-Security-Policy
- Not sent
- Strict-Transport-Security
- Not sent
- X-Frame-Options
- Not sent
- X-Content-Type-Options
- Not sent
- Referrer-Policy
- Not sent
- Permissions-Policy
- Not sent
Redirect chain
- 1.
http://fftw.org/HTTP 200
Meta tags
- Title
- FFTW Home Page
- Description
- A fast, free C FFT library; includes real-complex, multidimensional, and parallel transforms. Benchmarked against many other FFTs.
- Canonical
- Not set
- Robots
- Not set
- Generator
- Not set
- Open Graph title
- Not set
- Open Graph description
- Not set
- Open Graph image
- Not set
- Open Graph type
- Not set
- Twitter card
- Not set
- Twitter title
- Not set
- Twitter image
- Not set
robots.txt
- Disallow rules (User-agent: *)
- 3
- Disallow rules (other agents)
- 0
No Sitemap declared in robots.txt.
Technology detected
Best-effort, based on a small set of well-known signals — this may be incomplete.
- Cloudflarecdn
Server: cloudflare
Related domains
Similar connectivity
Domains ranked just above and below it in the same snapshot.