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Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
89
GRADE
B
FIX
0
REVIEW
3
PASS
6
INFO
0
Probed from Madrid, Spain
403 Forbidden
Checks
9
6 PASS 3 REVIEW
C
IPv6 Readiness
Action
No IPv6 support
REVIEW
No IPv6 support
Info::
No IPv6 (AAAA) records found
IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.
No IPv6 Support
About 40% of internet users have IPv6. Consider adding AAAA records.

IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

Why this matters

No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.

Source: Google IPv6 stats

B
TLS Certificate Expiry & Recommendations
89 days until leaf cert expires — 2 issues to address
REVIEW

Certificate validity

89
days left
0d 30d 60d 90d+

Recommended actions

  • Enable HSTS: Strict-Transport-Security: max-age=31536000; includeSubDomains
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
B
CDN & Delivery
Cloudflare
REVIEW
Cloudflare
Info::
Site is served via Cloudflare CDN (edge: CDG)
Got: cf-ray: 9efff6981e9e6f4c-CDG
CDN Detected: Cloudflare
Provider Cloudflare Evidence cf-ray: 9efff6981e9e6f4c-CDG
A+
DNS Records
2 A records, 94 ms lookup
PASS
2 A records, 94 ms lookup
Info::
Resolves to 2 IPv4 address(es)
Got: 104.16.134.27, 104.16.133.27
Info::
No IPv6 (AAAA) records
Info::
2 nameserver(s) configured
Got: ian.ns.cloudflare.com, lily.ns.cloudflare.com
Info::
7 mail exchanger(s) configured
Info::
CAA records not checked
CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
Info::
SPF record present in TXT
Info::
DNS resolution time: 94 ms
Got: 94 ms
A104.16.134.27, 104.16.133.27
AAAA—
CNAME—
NSian.ns.cloudflare.com, lily.ns.cloudflare.com
MX
10 aspmx.l.google.com
20 alt1.aspmx.l.google.com
30 alt2.aspmx.l.google.com
40 aspmx2.googlemail.com
50 aspmx3.googlemail.com
60 aspmx4.googlemail.com
70 aspmx5.googlemail.com
TXT
SPF v=spf1 include:spf.mtasv.net include:_spf.google.com include:sendgrid.net includ...
onetrust-domain-verification=7316088ca8db44f78ca82d9e961f6442
apple-domain-verification=GhqRH5BdB8mVkDUq
openai-domain-verification=dv-5Nx1YJVH5ae1OqCzL1NiNOu0
_c6ifay1uuzwpf3c6q917aojjdd6p1ea
google-site-verification=zwWiKvbXdW7mObtno1aea-OcQHXpmaZ2CvcW3qclYnA
facebook-domain-verification=pzag31nnjljvy81xhps4rggqtj46rq
PAEZFEC4AVFC77KOVF1R0H57BRTMST936SZT1YXT
24F3373645
cursor-domain-verification-nvvmrz=MJvAnXKyNFtJKJABZah0XyVgc
6bc7fbl8y9h6lng2n9mfymp16dy63g5s
docusign=a6f2c83c-9542-4ba7-92e3-032b45a00375
762642896-4167472
atlassian-domain-verification=plVFZkxuXPVmwzDvcpY5wv9jzzqQtxQtByhFAEdY+P7nj9p8sn...
hcp-domain-verification=0610f95c7b0e248dd930b7076e658fa93c1a08ccfa5f91e96b612919...
google-site-verification=W5dcXTOxPUzVvjBMgdJzZSMSebqrWo0O6CBV0FN1dhY
google-site-verification=5qTpwRH3290N26h2y-Dt-SOmOyX8xLramCneO4W9nDs
pinterest-site-verification=ea81483d36f8c1be6f86693a81004261
anthropic-domain-verification-c3qp9g=07K3uDxfCV06dDvwrJXNZeulX
K6b3CtLBfcqpRDNJfg7WcyP9qg
MS=ms29141506
onetrust-domain-verification=31c369ac7a3544d19c07ea059d09b5f3
CAALookup not available with standard resolver
Resolved in 94 ms

CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.

Why this matters

Informational: CAA (Certification Authority Authorization) records weren't checked in this scan.

A+
Redirect Chain
0 redirect(s), 65 ms total
PASS
0 redirect(s), 65 ms total

https://quizlet.com

65 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://quizlet.com40365 msHTTP/1.1cloudflare
A
Crawlability
robots.txt present, no sitemap
PASS
robots.txt present, no sitemap
Info::
robots.txt is present
Got: 3308 bytes
Info::
No sitemap.xml found
A sitemap helps search engines discover and index your pages more efficiently.
Info::
robots.txt references sitemap

A sitemap helps search engines discover and index your pages more efficiently.

Why this matters

No sitemap.xml — Google relies on crawl-graph discovery alone, slowing indexing of deep or fresh URLs.

Learn more ▾

A sitemap accelerates Google's discovery of new and updated content. Most CMSes auto-generate one; static-site frameworks need a build-step plugin. Reference it from robots.txt and submit in Search Console to confirm Google can fetch it.

Source: sitemaps.org / Google Search Central

robots.txt 200 OK
Size 3308 B Sitemaps referenced 12 User-agents FacebookBot, peer39_crawler, Google-Extended, CCBot, PerplexityBot, ChatGPT-User, omgilibot, anthropic-ai, cohere-ai, omgili, TextRazor, ClaudeBot, Claude-Web, Amazonbot, magpie-crawler, peer39_crawler/1.0, *, GPTBot, Bytespider, OAI-SearchBot, AwarioSmartbot, DataForSeoBot Blocking No — crawling allowed
User-agent: *
Allow: /*-diagram
Allow: /*-flash-cards
Allow: /features
Allow: /study-guides/

Sitemap: https://quizlet.com/special-sitemap-index.xml
Sitemap: https://quizlet.com/special-sitemap-5sets-index.xml
Sitemap: https://quizlet.com/special-sitemap-6sets-index.xml
Sitemap: https://quizlet.com/special-sitemap-7sets-index.xml
Sitemap: https://quizlet.com/sitemap_index-notes.xml
Sitemap: https://quizlet.com/special-sitemap-content.xml
Sitemap: https://quizlet.com/au/sitemap_index-flashcard_au.xml
Sitemap: https://quizlet.com/au/sitemap_index-diagram_au.xml
Sitemap: https://quizlet.com/ca/sitemap_index-flashcard_ca.xml
Sitemap: https://quizlet.com/ca/sitemap_index-diagram_ca.xml
Sitemap: https://quizlet.com/mx/sitemap_index-flashcard_mx.xml
Sitemap: https://quizlet.com/vn/sitemap_index-flashcard_vn.xml

Disallow: /*/autosave$
Disallow: /*/autosaved
Disallow: /*/classes$
Disallow: /*/delete$
Disallow: /*/edit-screen
Disallow: /*/edit$
Disallow: /*/embed/
Disallow: /*/embed$
Disallow: /*/export/
Disallow: /*/export$
Disallow: /*/folders$
Disallow: /folders/*/*
Disallow: /user/*/folders/*/*
Disallow: /*/info/
Disallow: /*/info$
Disallow: /*/learn/embed
Disallow: /*/match/embed
Disallow: /*/new/
Disallow: /*/new$
Disallow: /*/print$
Disallow: /*/recreate_set
Disallow: /*/recreate-set
Disallow: /*/scores/
Disallow: /*/scores$
Disallow: /*/simple$
Disallow: /*/spell/embed
Disallow: /*/starred$
Disallow: /*/view-screen
Disallow: /*/write/embed
Disallow: /ajax
Disallow: /fb-oauth-redirector
Disallow: /google-oauth-redirector
Disallow: /hello-quizlet
Disallow: /join
Disallow: /login?redir=
Disallow: /notes/sample-essay-questions/
Disallow: /oauth-extra-info
Disallow: /pdfs
Disallow: /practice-test/
Disallow: /practice-test/*/results
Disallow: /qzadmin
Disallow: /renderer/
Disallow: /studiable-item-documents
Disallow: /tts
Disallow: /uc/*
Disallow: /webapi/
Disallow: /search
Disallow: /ai-flashcards/

#AI Training Bots
User-agent: GPTBot
User-agent: Google-Extended
User-agent: CCBot
User-agent: anthropic-ai
User-agent: ClaudeBot
User-agent: Claude-Web
User-agent: Bytespider
User-agent: PerplexityBot
Disallow: /

#AI Search Bots
User-agent: OAI-SearchBot
Allow: /
Disallow: /user
Disallow: /folders
Disallow: /class
Disallow: /explanations
Disallow: /learn
Disallow: /schools
Disallow: /qzadmin
Disallow: /fb-oauth-redirector
Disallow: /google-oauth-redirector
Disallow: /oauth
Disallow: /hello-quizlet

#Other Bots
User-agent: ChatGPT-User
User-agent: Amazonbot
User-agent: AwarioSmartbot
User-agent: cohere-ai
User-agent: DataForSeoBot
User-agent: FacebookBot
User-agent: magpie-crawler
User-agent: omgili
User-agent: omgilibot
User-agent: peer39_crawler
User-agent: peer39_crawler/1.0
Disallow: /explanations
Disallow: /learn
Disallow: /users

User-agent: TextRazor
Allow: /

#  ________  ___  ___  ___  ________  ___       _______  _________
# |\   __  \|\  \|\  \|\  \|\_____  \|\  \     |\  ___ \|\___   ___\
# \ \  \|\  \ \  \\\  \ \  \\|___/  /\ \  \    \ \   __/\|___ \  \_|
#  \ \  \\\  \ \  \\\  \ \  \   /  / /\ \  \    \ \  \_|/__  \ \  \
#   \ \  \\\  \ \  \\\  \ \  \ /  /_/__\ \  \____\ \  \_|\ \  \ \  \
#    \ \_____  \ \_______\ \__\\________\ \_______\ \_______\  \ \__\
#     \|___| \__\|_______|\|__|\|_______|\|_______|\|_______|   \|__|
#           \|__|
sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

A+
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
PASS
www/non-www, trailing slash, HTTP→HTTPS
Info::
www/non-www redirect configured correctly (preferred: non-www)
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

301https://www.quizlet.com/
200https://quizlet.com/

Preferred variant: non-www

HTTP → HTTPS

301http://quizlet.com/ → https://quizlet.com/

Consistent

A
Domain Intelligence
quizlet.com — via GoDaddy.com, LLC, 22 years, 1 months old, hosted on Cloudflare
PASS
quizlet.com — via GoDaddy.com, LLC, 22 years, 1 months old, hosted on Cloudflare
Warning::
Domain expires in 84 days
Consider enabling auto-renewal to prevent accidental expiration.
Got: Expires Jul 15, 2026
Info::
DNSSEC is enabled
Info::
Registrar: GoDaddy.com, LLC
Warning::
Registrar lock is NOT enabled
The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.
Info::
Hosting: Cloudflare
Got: AS13335
Domain expiry

EXPIRED

July 15, 2026

SSL certificate

89 days

Issued by Let's Encrypt

Domain age

22 years, 1 months

Registered July 15, 2004

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

Cloudflare

ASN AS13335

104.16.133.27

Registrar

GoDaddy.com, LLC

Unlocked 2 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Domain has EXPIRED — renew immediately to avoid total site outage
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar GoDaddy.com, LLC
Created July 15, 2004 (22 years, 1 months ago)
Expires July 15, 2026 (2 months)
Last Updated July 16, 2023
Name Servers cns1.quizlet.com, cns2.quizlet.com
DNSSEC Enabled
Hosting
IP Address 104.16.133.27
ASN AS13335 (CLOUDFLARENET - Cloudflare, Inc., US)
Provider Cloudflare
Data source: rdap (0.3s)

Consider enabling auto-renewal to prevent accidental expiration.

Why this matters

Domain expiry approaching — renew immediately and ensure auto-renew + alerting are configured.

Source: ICANN renewal policy

The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.

Why this matters

Without registrar lock, an attacker who phishes your registrar credentials can transfer the domain in minutes — total brand hijack.

Learn more ▾

Registrar lock (clientTransferProhibited, clientUpdateProhibited, clientDeleteProhibited) requires extra verification before any transfer/update/delete. Every major registrar offers it free. Combined with 2FA on your registrar account, it's the strongest defense against domain hijacking.

Source: ICANN / domain-security best practice

A+
HTTP Probe Timing
Total 96 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
31 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
17 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
22 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
96 ms
Total Time Total request time from DNS lookup through full response.
97 ms

Connection waterfall

DNS Lookup 31 ms TCP Connect 17 ms TLS Handshake 22 ms Server Processing 27 ms Content Transfer 0 ms
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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