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https://leetcode.com

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
95
GRADE
A
FIX
0
REVIEW
3
PASS
6
INFO
0
Probed from Madrid, Spain
403 Forbidden
Checks
9
6 PASS 3 REVIEW
B
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
REVIEW
www/non-www, trailing slash, HTTP→HTTPS
Critical::
HTTP version does not redirect to HTTPS
Got: HTTP 403 Expected: 301 redirect to HTTPS

www / non-www

403https://www.leetcode.com/
200https://leetcode.com/

HTTP → HTTPS

403http://leetcode.com/

HTTP version does not redirect to HTTPS

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

Certificate validity

83
days left
0d 30d 60d 90d+

Recommended actions

  • Extend HSTS max-age to at least 31536000 (1 year) to meet the preload list criteria
  • 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: 9f0097f17b6099a4-CDG
CDN Detected: Cloudflare
Provider Cloudflare Evidence cf-ray: 9f0097f17b6099a4-CDG
A+
DNS Records
2 A records, 31 ms lookup
PASS
2 A records, 31 ms lookup
Info::
Resolves to 2 IPv4 address(es)
Got: 104.20.41.79, 172.66.154.160
Info::
Has 2 IPv6 (AAAA) record(s)
Got: 2606:4700:10::ac42:9aa0, 2606:4700:10::6814:294f
Info::
2 nameserver(s) configured
Got: melinda.ns.cloudflare.com, rob.ns.cloudflare.com
Info::
5 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: 31 ms
Got: 31 ms
A104.20.41.79, 172.66.154.160
AAAA2606:4700:10::ac42:9aa0, 2606:4700:10::6814:294f
CNAME—
NSmelinda.ns.cloudflare.com, rob.ns.cloudflare.com
MX
1 aspmx.l.google.com
5 alt1.aspmx.l.google.com
5 alt2.aspmx.l.google.com
10 alt3.aspmx.l.google.com
10 alt4.aspmx.l.google.com
TXT
google-site-verification=uPA2Afaqn3DS4X4oaTesCU4ucbWXEdQXhdtyre0mdmg
SPF v=spf1 include:amazonses.com include:_spf.google.com include:mail.zendesk.com in...
domain-verification=6265d606aef4f770bf52dccbf18644e645dcada2b1ec0ce5a6061fb49cd5...
google-site-verification=ds0HPGUEYOzxPbBHmhQUrjDGv2-jKNpAOYcYK0dhSlw
CAALookup not available with standard resolver
Resolved in 31 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), 62 ms total
PASS
0 redirect(s), 62 ms total

https://leetcode.com

62 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://leetcode.com40362 msHTTP/1.1cloudflare
A+
IPv6 Readiness
IPv6 reachable (17 ms)
PASS
IPv6 reachable (17 ms)
Info::
IPv6 is configured and reachable at 2606:4700:10::ac42:9aa0, 2606:4700:10::6814:294f
Got: 17 ms connect
IPv6 Ready
AAAA Records 2606:4700:10::ac42:9aa0, 2606:4700:10::6814:294f Connection Reachable (17 ms)
A+
Crawlability
robots.txt present, sitemap with 50 URLs
PASS
robots.txt present, sitemap with 50 URLs
Info::
robots.txt is present
Got: 514 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 50 entries
Info::
Sitemap index with 50 child sitemaps
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 514 B Sitemaps referenced 1 User-agents * Blocking No — crawling allowed
User-agent: *
Disallow: /submissions
Disallow: /api/
Disallow: /*/api
Disallow: /problems/random-one-question
Disallow: /accounts
Disallow: /contest/*/problems
Disallow: /playground
Disallow: /subscription
Disallow: /list
Disallow: /notes
Disallow: /session
Disallow: /progress
Disallow: /points
Disallow: /library
Disallow: /forums
Disallow: /discuss/index.php
Disallow: /problems/*/interpret_solution
Disallow: /problems/*/submit
Disallow: /graphql

Host: leetcode.com
Sitemap: https://leetcode.com/sitemap.xml
sitemap.xml 200 OK
Type Sitemap Index URLs 50 entries Valid XML Yes
Child Sitemaps:
A+
Domain Intelligence
leetcode.com — via GoDaddy.com, LLC, 16 years old
PASS
leetcode.com — via GoDaddy.com, LLC, 16 years old
Info::
Domain registered until Jul 11, 2034 (8 years, 4 months remaining)
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.
Domain expiry

2915 days

July 11, 2034

SSL certificate

83 days

Issued by Google Trust Services

Domain age

16 years

Registered July 11, 2010

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

Unknown

2606:4700:10::6814:294f

Registrar

GoDaddy.com, LLC

Unlocked 2 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar GoDaddy.com, LLC
Created July 11, 2010 (16 years ago)
Expires July 11, 2034 (8 years, 4 months)
Last Updated March 25, 2025
Name Servers melinda.ns.cloudflare.com, rob.ns.cloudflare.com
DNSSEC Enabled
Hosting
IP Address 2606:4700:10::6814:294f
Data source: rdap (0.2s)

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 94 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.
16 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.
94 ms
Total Time Total request time from DNS lookup through full response.
94 ms

Connection waterfall

DNS Lookup 31 ms TCP Connect 16 ms TLS Handshake 22 ms Server Processing 25 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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