What technology does android-api-cf.duolingo.com use?

We did not detect any specific technologies for android-api-cf.duolingo.com in the latest scan.

Is android-api-cf.duolingo.com secure (HTTPS)?

Yes. android-api-cf.duolingo.com uses TLS 1.3 with a certificate issued by Amazon, valid until Dec 24, 2026.

Who hosts android-api-cf.duolingo.com?

Hosting provider information for android-api-cf.duolingo.com is not available yet.

What is android-api-cf.duolingo.com's SEO score?

android-api-cf.duolingo.com scored 70/100 for SEO in the latest analysis (fair).

What is android-api-cf.duolingo.com's overall website score?

android-api-cf.duolingo.com has an overall SiteGraph score of 81/100, combining SEO, performance, security, and accessibility.

Has android-api-cf.duolingo.com's score changed over time?

android-api-cf.duolingo.com's overall score has declined by 2 points (from 83 to 81) since Jul 23, 2026.

android-api-cf.duolingo.com

Duolingo

Last scanned Jul 31, 2026, 12:00 AM · 10 views

Overall score

Great

Summary

Duolingo is the world's most popular way to learn a language. SEO is fair (70/100) and accessibility is good (80/100). Security scores good (75/100) and performance excellent (100/100). Top issue: No H1 heading found.

Duolingo is the world's most popular way to learn a language. It's 100% free, fun and science-based. Practice online on duolingo.com or on the apps!

Top issues to fix

8 issues found · 3 high priority

Missing Strict-Transport-Security header
Security
Add HSTS so browsers always use HTTPS — this closes the protocol-downgrade attack window.
Missing Content-Security-Policy header
Security
Add a CSP to control which sources can run scripts — the strongest single defense against XSS.
No H1 heading found
SEO
Add exactly one H1 describing the page's main topic — it anchors the document outline for search engines and screen readers.
Missing X-Content-Type-Options header
Security
Add X-Content-Type-Options: nosniff to stop MIME-sniffing attacks.
No structured data (JSON-LD) found
SEO
Add JSON-LD (Organization, Article, Product…) to become eligible for rich results.
robots.txt not found
SEO
Publish /robots.txt with a Sitemap: directive to guide crawlers.

+2 more issues — details in the sections below.

SEO

4 issue(s) found

100

Performance

214 ms

Security

HTTPS & header checks

Accessibility

2 issue(s) found

Score history

-2 overall since Jul 23, 2026

Overall: 81
SEO: 70
Security: 75
Performance: 100
Accessibility: 80

Organization

Company details published in this site's own structured data.

Duolingo is the world's most popular way to learn a language. It's 100% free, fun and science-based. Practice online on duolingo.com or on the apps!

Meta tags

Title: Duolingo
Description: Duolingo is the world's most popular way to learn a language. It's 100% free, fun and science-based. Practice online on duolingo.com or on the apps!
Canonical: https://android-api-cf.duolingo.com/
Language
Charset: utf-8
Viewport: width=device-width,initial-scale=1,user-scalable=no
Robots meta: NOODP
Manifest: https://android-api-cf.duolingo.com/manifest.json

Technologies

Detected frameworks, languages, and tools.

No technologies detected.

Hosting & CDN

Hosting provider: —
CDN provider: CloudFront
IP address: —
ASN: —

DNS records

Type	Value
A	—
AAAA	—
MX	—
TXT	—
NS	—
CAA	—
CNAME	—
IPv6 support	No

TLS / SSL certificate

Version: TLS 1.3
Issuer: Amazon
Subject: *.duolingo.com
Valid from: Nov 25, 2025
Valid to: Dec 24, 2026
Days until expiry: 146
SAN domains: *.duolingo.com

Security headers

Strict-Transport-SecurityMissing
Content-Security-PolicyMissing
X-Frame-OptionsEnabled
X-Content-Type-OptionsMissing
Referrer-PolicyMissing
Permissions-PolicyMissing

Compression: gzip · 0 cookie(s) observed

Content & assets

Headings

H1 0 · H2 0 · H3 0

Links

0 internal · 0 external · 0 broken

Images

0 total · 0 missing alt

Scripts / Styles

14 scripts · 2 stylesheets

JS / CSS size

4.7 KB · 0 B

Page size

11.0 KB

Robots.txt & Sitemap

robots.txt: Not found
Disallow rules: 0
sitemap.xml: Not found
URLs in sitemap: 0

SEO issues

No H1 heading found
No structured data (JSON-LD) found
robots.txt not found
sitemap.xml not found

Scan details

Requested URL: https://android-api-cf.duolingo.com
Final URL: https://android-api-cf.duolingo.com
HTTP status: 200
HTTP version: HTTP/2
Response time: 214 ms
HTML size: 11.0 KB
Redirect chain: https://android-api-cf.duolingo.com

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Frequently asked questions

What technology does android-api-cf.duolingo.com use?: We did not detect any specific technologies for android-api-cf.duolingo.com in the latest scan.
Is android-api-cf.duolingo.com secure (HTTPS)?: Yes. android-api-cf.duolingo.com uses TLS 1.3 with a certificate issued by Amazon, valid until Dec 24, 2026.
Who hosts android-api-cf.duolingo.com?: Hosting provider information for android-api-cf.duolingo.com is not available yet.
What is android-api-cf.duolingo.com's SEO score?: android-api-cf.duolingo.com scored 70/100 for SEO in the latest analysis (fair).
What is android-api-cf.duolingo.com's overall website score?: android-api-cf.duolingo.com has an overall SiteGraph score of 81/100, combining SEO, performance, security, and accessibility.
Has android-api-cf.duolingo.com's score changed over time?: android-api-cf.duolingo.com's overall score has declined by 2 points (from 83 to 81) since Jul 23, 2026.