Website readiness profile · Snapshot 23 October 2026
duolingo.com
duolingo.com's public homepage, certificate and DNS checked against 31 practices and compared with 1,516 Education & Online Learning sites.
- Readiness index
- 62/100
- Ahead of
- 52%
- Practices observed
- 14/28
- Popularity band
- Top 5K
Education & Online Learning median 61
of measured Education & Online Learning sites
3 of 31 could not be measured
Chrome UX Report top-sites list
Readiness by lane
Green: duolingo.com. Thin bar: Education & Online Learning peer median.
Enable
79/100
Peers 75
Harden
54/100
Peers 54
Accelerate
63/100
Peers 57
Recover
0/100
Peers 13
Priority fixes for duolingo.com
Ordered by impact and by how common each practice is among peers.
Priority 1 · Harden
HSTS kept for at least a year
Observed: The homepage response did not include a Strict-Transport-Security header.
Why it matters: HSTS tells browsers to use HTTPS for your host on every later visit, which removes the window where a first HTTP request can be intercepted.
What to do: 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 Amazon CloudFront: Attach a response headers policy with Strict-Transport-Security to each distribution.
34% of Education & Online Learning peers do this. Limit: Read from the homepage response only; other pages or regions may send different headers.
Priority 2 · Accelerate
No render-blocking scripts in <head>
Observed: The homepage <head> loaded 1 external script without async or defer.
What to do: Add defer to scripts that need the DOM, async to independent ones such as analytics, or move them to the end of the body.
42% of Education & Online Learning peers do this.
Guide: Control Third-Party Scripts Before They Control Your Page
Priority 3 · Enable
Page language declared
Observed: The homepage <html> element had no lang attribute.
What to do: Set lang on the html element (for example lang="en") and on any sections in another language.
91% of Education & Online Learning peers do this.
Priority 4 · Harden
Certificate lifetime of 100 days or less
Observed: The certificate from Amazon had a 394-day validity period, longer than the 100-day maximum that applies from March 2027.
What to do: Move to automated issuance and renewal now, while you still have time to test it.
60% of Education & Online Learning peers do this.
What duolingo.com already does well
Practices fewer than half of Education & Online Learning peers use.
- DMARC policy enforces quarantine or rejectDMARC policy p=reject.36% of peers
- Framing restrictedFraming controls present.49% of peers
What we saw
- Homepage checked
- https://www.duolingo.com/
- Homepage response
- HTTP 200
- TLS
- TLSv1.3, HTTP/2
- Certificate
- Amazon, 394-day validity, expiring 2026-12-24
- CDN or edge
- Amazon CloudFront
- DNS operators
- Amazon Route 53
- DMARC policy
- p=reject
- Homepage HTML
- 11 KB, gzip
- Images on homepage
- 0
Limits: homepage only, one location, one moment. Header checks reflect the homepage response; other pages may differ.
Stack and providers
Seen in the homepage response, certificate and DNS. Provider pages compare how their customers configure the same checks.
All 31 checks
Select a gap for the method and fix. How each check works
Not observed 14
- HSTS kept for at least a year
- Certificate lifetime of 100 days or less
- CAA records limit who can issue certificates
- DNSSEC signed
- security.txt published
- X-Content-Type-Options: nosniff
- Content Security Policy present
- Referrer-Policy set
- HTTP/3 advertised
- No render-blocking scripts in <head>
- Reachable over IPv6
- Structured data present
- Page language declared
- Nameservers spread across providers
Observed 14
- HTTP requests move to HTTPS
- TLS 1.3 negotiated
- Certificate has more than 14 days left
- DMARC policy enforces quarantine or reject
- Framing restricted
- HTTP/2 negotiated
- HTML compressed
- robots.txt published
- XML sitemap discoverable
- Canonical URL declared
- Meta description written
- Mobile viewport configured
- Social preview image set
- At most one redirect to the homepage
Not measured 3
- Static files cached for 30 days or more
- Modern image formats in use
- Offscreen images lazy-loaded
Own duolingo.com?
Re-run the checks after a change, keep a private action plan in a free workspace, or report a mistake.
Live status for this site: Status Is Down: duolingo.com. This profile covers configuration only.