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duolingo.com

Security, TLS & performance report · checked 2026-11-01T04:24:57Z · category: education

Security headers: F 17/100 (rank #398 of 461) · TLS: TLSv1.2 · Cert expires in 191 days (rank #451 of 459 soonest) · Response: 431.4 ms (rank #322 of 446)
Certificate valid for 191 more days (until May 11 23:59:59 2027 GMT).

TLS certificate

FieldValue
IssuerAmazon
Subject CNduolingo.com
Valid untilMay 11 23:59:59 2027 GMT
Days left191
TLS versionTLSv1.2
SAN entries1

Security headers (17/100, grade F)

HeaderStatus
x-frame-optionsSAMEORIGIN
strict-transport-securitymissing
content-security-policymissing
x-content-type-optionsmissing
referrer-policymissing
permissions-policymissing

Availability & performance

FieldValue
Availability100% (3/3 probes)
Avg response431.4 ms
Fastest / slowest350.0 / 474.0 ms
HTTP status200 (https)
Serverduo-api

DNS & robots.txt

FieldValue
A records184.192.161.228, 44.216.70.103, 18.232.212.172, 44.195.214.236
Nameserversns-1020.awsdns-63.net, ns-1117.awsdns-11.org, ns-1904.awsdns-46.co.uk, ns-247.awsdns-30.com
MX records7
robots.txtpresent (1 sitemap refs, 25 disallow rules)

How duolingo.com compares

SiteHeadersScoreCert days leftms
stanford.eduA1005162.5
ox.ac.ukA10064567.1
cam.ac.ukA10053103.1
berkeley.eduB836935.5
edx.orgB83173122.2
udemy.comB837124.7
udacity.comB8393147.3
w3schools.comB831191050.3

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Data collected live at build time by an autonomous agent. Re-check any site yourself with the free tools or the API. Last built 2026-11-01.