Stack playbook · Snapshot 23 October 2026
Astro on Cloudflare: readiness playbook
What 334 measured sites on this stack get right, where they fall short, and the Astro on Cloudflare-specific steps that close each gap.
- Sites measured
- 334
- Median readiness index
- 75/100
- Profiles on this stack
- 54
detected from homepage HTML and headers
all sites: 64
top-50K sites
Readiness by lane
Enable
92/100
All sites 77
Harden
61/100
All sites 55
Accelerate
86/100
All sites 63
Recover
8/100
All sites 11
The Astro on Cloudflare playbook
Gaps ordered by impact, with the platform-specific step where one exists.
HSTS kept for at least a year
39% observed · all sites 31%
Send Strict-Transport-Security on HTTPS responses. Start with a short max-age (for example 300 seconds), confirm every subdomain works over HTTPS, then raise it in steps to 31536000. Add includeSubDomains only when all subdomains are HTTPS. HSTS preload is optional and hard to undo; hstspreload.org itself does not recommend it by default.
On Cloudflare: Enable HSTS under SSL/TLS > Edge Certificates > HTTP Strict Transport Security and raise max-age gradually.
security.txt published
11% observed · all sites 5.5%
Publish /.well-known/security.txt with at least Contact and Expires fields, as RFC 9116 requires, and review it before it expires.
On Cloudflare: Cloudflare Security Center can serve a security.txt file for the zone.
DMARC policy enforces quarantine or reject
43% observed · all sites 31%
Publish DMARC with p=none and a reporting address first, fix any legitimate senders that fail SPF or DKIM alignment, then move to quarantine and finally reject.
CAA records limit who can issue certificates
14% observed · all sites 11%
Publish CAA records naming every CA you actually use, including the CAs your CDN uses for managed certificates. Add an iodef contact if you want reports.
On Cloudflare: Cloudflare documents which CAs its managed certificates need; include them in your CAA records.
Content Security Policy present
31% observed · all sites 31%
Start with Content-Security-Policy-Report-Only to see what would break, tighten the policy over a few weeks, then enforce it.
Guide: Payment Security and PCI DSS: What Website Owners Need to Know
DNSSEC signed
12% observed · all sites 8.1%
Enable DNSSEC at your DNS provider, then add the DS record at your registrar. Plan provider moves carefully: a stale DS record can make the domain fail to resolve.
On Cloudflare: Enable DNSSEC in DNS > Settings and add the DS record at the registrar.
Guide: Website Uptime Readiness: Prepare Before Traffic Arrives
Static files cached for 30 days or more
65% observed · all sites 50%
Give versioned (fingerprinted) CSS, JavaScript, fonts and images Cache-Control: public, max-age=31536000, immutable, and change the file name whenever the content changes.
On Cloudflare: Use Cache Rules to set edge and browser TTLs for static file paths.
Framing restricted
50% observed · all sites 49%
Send Content-Security-Policy: frame-ancestors 'self' (or a list of trusted origins). X-Frame-Options: SAMEORIGIN covers older browsers.
On Cloudflare: Add the header with a response header transform rule.
Where Astro on Cloudflare sites lead
- No render-blocking scripts in <head>87% observedall sites 44%
- Reachable over IPv685% observedall sites 44%
- Modern image formats in use78% observedall sites 40%
- HTTP/3 advertised70% observedall sites 36%