go.dev

24 hours
100.00%
7 days
100.00%
30 days
100.00%
IPv4 / IPv6
4 4
SSL Certificate
86d
Security Headers
2/6
Badges: Uptime Status
Response Time & Availability (24h)
SSL / TLS Certificate
86
days left
Valid
Apr 8, 2026 Jul 7, 2026
Issued → Expires
Subject commonName=go.dev
Issuer countryName=US, organizationName=Google Trust Services, commonName=WR3
Valid From 2026-04-08 09:35
Expires 2026-07-07 10:25
Serial Number 1FEEB52C3F163EBD0A74627A896B6B30
SHA-256 Fingerprint 2a:31:7f:1f:5d:82:67:af:03:b6:8e:ee:6b:37:4e:63:5f:76:da:80:bc:5b:df:35:14:2c:c1:77:46:1f:12:e2
Subject Alt Names go.dev
Last Checked 2026-04-11 21:53:30
Latest HTTP Response Details
Final URL https://go.dev/
Status Code 200
Response Time 190 ms
Content Size 63 KB (62.5 KB)
Content Type text/html; charset=utf-8
Server Google Frontend
TLS Version TLSv1.3
TLS Cipher TLS_AES_256_GCM_SHA384
Redirects 0
Checked 2026-04-11 21:53:29
Security Headers 2/6
Header Status Value
Strict-Transport-Security Present max-age=31536000; includeSubDomains; preload
Content-Security-Policy Present connect-src 'self' www.google-analytics.com stats.g.doubleclick.net ; default-src 'self' ; font-src 'self' fonts.googleapis.com fonts.gstatic.com data: ; frame-ancestors 'self' ; frame-src 'self' www.google.com feedback.googleusercontent.com www.googletagmanager.com scone-pa.clients6.google.com www.youtube.com player.vimeo.com ; img-src 'self' www.google.com www.google-analytics.com ssl.gstatic.com www.gstatic.com gstatic.com data: * ; object-src 'none' ; script-src 'self' 'sha256-n6OdwTrm52KqKm6aHYgD0TFUdMgww4a0GQlIAVrMzck=' 'sha256-4ryYrf7Y5daLOBv0CpYtyBIcJPZkRD2eBPdfqsN3r1M=' 'sha256-sVKX08+SqOmnWhiySYk3xC7RDUgKyAkmbXV2GWts4fo=' www.google.com apis.google.com www.gstatic.com gstatic.com support.google.com www.googletagmanager.com www.google-analytics.com ssl.google-analytics.com tagmanager.google.com ; style-src 'self' 'unsafe-inline' fonts.googleapis.com feedback.googleusercontent.com www.gstatic.com gstatic.com tagmanager.google.com ;
X-Frame-Options Missing
X-Content-Type-Options Missing
Referrer-Policy Missing
Permissions-Policy Missing
DNS Intelligence (24h)
Avg Resolution
23.7 ms
Min / Max
4.3 / 41.8 ms
Record Types
8
Lookups (24h)
45
DNS Records
A
216.239.32.21 216.239.38.21 216.239.34.21 216.239.36.21
300s 33.2ms
AAAA
2001:4860:4802:38::15 2001:4860:4802:34::15 2001:4860:4802:36::15 2001:4860:4802:32::15
300s 21.8ms
MX
1 aspmx.l.google.com
5 alt2.aspmx.l.google.com
5 alt1.aspmx.l.google.com
10 alt3.aspmx.l.google.com
10 alt4.aspmx.l.google.com
300s 20.1ms
NS
ns-cloud-e1.googledomains.com ns-cloud-e3.googledomains.com ns-cloud-e2.googledomains.com ns-cloud-e4.googledomains.com
21600s 19.3ms
TXT
Domain Verification (5)
google-site-verification=eqtrduRyMRS8TuoUEuYMF-u9_IDRMd1In6T6E1gTchU
google-site-verification=mJdpiJi2GyNG9nz7sctCXgJnzDHzdFzfhOqTTDuMR0s
google-site-verification=qvibgBDBD_1VeFXvgduqw1cmDeMpAS_qBCZCFauYduk
google-site-verification=eYE-BIP9BY8VZCUI_r8sJi7qjRVtxyRQSlbZmeVVlzE
google-site-verification=3oHHTSOKrjE9J8SIvyj3gUxEtDjmr5oNZ-DbB271vpM
300s 19.3ms
SOA
Primary NS
ns-cloud-e1.googledomains.com
Admin
cloud-dns-hostmaster@google.com
Serial: 1 Refresh: 6h Retry: 1h Expire: 3d Min TTL: 5m
21600s 17.8ms
CAA
Flag Tag Value
0 issue letsencrypt.org
0 issue pki.goog
300s 18.0ms
PTR
any-in-2001-4860-4802-38--15.1e100.net
86400s 172.6ms
Email Security Posture
MX Records
SPF
DMARC
BIMI
MTA-STS
Weak
Overall
DNS Propagation Consistent
Resolver IPs Returned Response Time Status
Quad9 216.239.32.21 216.239.34.21 216.239.36.21 216.239.38.21 31.13ms
Google 216.239.32.21 216.239.34.21 216.239.36.21 216.239.38.21 13.37ms
AdGuard 216.239.32.21 216.239.34.21 216.239.36.21 216.239.38.21 80.5ms
OpenDNS 216.239.32.21 216.239.34.21 216.239.36.21 216.239.38.21 71.65ms
Cloudflare 216.239.32.21 216.239.34.21 216.239.36.21 216.239.38.21 21.32ms
WHOIS / Domain Registration
DNSSEC
WHOIS Last Checked
2026-04-11 21:53
Resolution Time (A/AAAA recent)
19:47 21:53
Time Type Values TTL Resolution Nameserver
21:53:28 PTR 2001:4860:4802:38::15 86400s 172.6 ms
21:53:28 PTR 2001:4860:4802:34::15 86400s 247.8 ms
21:53:28 PTR 2001:4860:4802:36::15 86400s 103.6 ms
21:53:28 PTR 216.239.34.21 83502s 3.9 ms
21:53:28 PTR 2001:4860:4802:32::15 86400s 82.6 ms
21:53:28 PTR 216.239.38.21 85086s 4.0 ms
21:53:28 PTR 216.239.32.21 86400s 30.8 ms
21:53:28 PTR 216.239.36.21 81394s 5.0 ms
21:53:28 CAA 0 issue "letsencrypt.org" 0 issue "pki.goog" 300s 18.0 ms 10.89.0.1
21:53:28 SOA ns-cloud-e1.googledomains.com cloud-dns-hostmaster.google.com 1 21600 3600 2592… 21600s 17.8 ms 10.89.0.1
21:53:28 TXT
5 records google-site-verification=eqtrduRyMRS8TuoUEuYMF-u9…
google-site-verification=eqtrduRyMRS8TuoUEuYMF-u9_IDRMd1In6T6E1gTchU google-site-verification=mJdpiJi2GyNG9nz7sctCXgJnzDHzdFzfhOqTTDuMR0s google-site-verification=qvibgBDBD_1VeFXvgduqw1cmDeMpAS_qBCZCFauYduk google-site-verification=eYE-BIP9BY8VZCUI_r8sJi7qjRVtxyRQSlbZmeVVlzE google-site-verification=3oHHTSOKrjE9J8SIvyj3gUxEtDjmr5oNZ-DbB271vpM
300s 19.3 ms 10.89.0.1
21:53:28 NS ns-cloud-e1.googledomains.com ns-cloud-e3.googledomains.com ns-cloud-e2.googledomains.com ns-cloud-e4.googledomains.com 21600s 19.3 ms 10.89.0.1
21:53:28 MX 5 alt2.aspmx.l.google.com 10 alt3.aspmx.l.google.com 5 alt1.aspmx.l.google.com 10 alt4.aspmx.l.google.com 1 aspmx.l.google.com 300s 20.1 ms 10.89.0.1
21:53:28 AAAA 2001:4860:4802:38::15 2001:4860:4802:34::15 2001:4860:4802:36::15 2001:4860:4802:32::15 300s 21.8 ms 10.89.0.1
21:53:28 A 216.239.32.21 216.239.38.21 216.239.34.21 216.239.36.21 300s 33.2 ms 10.89.0.1
20:50:12 PTR 2001:4860:4802:38::15 3382s 4.5 ms
20:50:12 PTR 2001:4860:4802:34::15 3383s 1.4 ms
20:50:12 PTR 216.239.38.21 3382s 0.8 ms
20:50:12 PTR 216.239.36.21 3383s 4.1 ms
20:50:12 PTR 2001:4860:4802:36::15 3382s 3.8 ms
20:50:12 PTR 216.239.32.21 3382s 1.4 ms
20:50:12 PTR 2001:4860:4802:32::15 3382s 1.8 ms
20:50:12 PTR 216.239.34.21 3382s 4.2 ms
20:50:12 CAA 0 issue "pki.goog" 0 issue "letsencrypt.org" 300s 21.6 ms 10.89.0.1
20:50:12 SOA ns-cloud-e1.googledomains.com cloud-dns-hostmaster.google.com 1 21600 3600 2592… 3382s 1.6 ms 10.89.0.1
20:50:12 TXT
5 records google-site-verification=3oHHTSOKrjE9J8SIvyj3gUxE…
google-site-verification=3oHHTSOKrjE9J8SIvyj3gUxEtDjmr5oNZ-DbB271vpM google-site-verification=eqtrduRyMRS8TuoUEuYMF-u9_IDRMd1In6T6E1gTchU google-site-verification=mJdpiJi2GyNG9nz7sctCXgJnzDHzdFzfhOqTTDuMR0s google-site-verification=qvibgBDBD_1VeFXvgduqw1cmDeMpAS_qBCZCFauYduk google-site-verification=eYE-BIP9BY8VZCUI_r8sJi7qjRVtxyRQSlbZmeVVlzE
300s 19.0 ms 10.89.0.1
20:50:12 NS ns-cloud-e4.googledomains.com ns-cloud-e2.googledomains.com ns-cloud-e1.googledomains.com ns-cloud-e3.googledomains.com 3382s 5.6 ms 10.89.0.1
20:50:12 MX 10 alt4.aspmx.l.google.com 5 alt1.aspmx.l.google.com 5 alt2.aspmx.l.google.com 1 aspmx.l.google.com 10 alt3.aspmx.l.google.com 300s 38.9 ms 10.89.0.1
20:50:12 AAAA 2001:4860:4802:38::15 2001:4860:4802:32::15 2001:4860:4802:34::15 2001:4860:4802:36::15 300s 21.3 ms 10.89.0.1
20:50:12 A 216.239.32.21 216.239.36.21 216.239.34.21 216.239.38.21 35s 4.3 ms 10.89.0.1
19:47:25 PTR 216.239.36.21 85975s 4.0 ms
19:47:25 PTR 2001:4860:4802:34::15 86400s 290.3 ms
19:47:25 PTR 2001:4860:4802:32::15 86400s 90.7 ms
19:47:25 PTR 2001:4860:4802:36::15 86400s 128.5 ms
19:47:25 PTR 216.239.34.21 86187s 3.7 ms
19:47:25 PTR 216.239.38.21 81822s 3.8 ms
19:47:25 PTR 2001:4860:4802:38::15 86400s 96.8 ms
19:47:25 PTR 216.239.32.21 77610s 4.6 ms
19:47:25 CAA 0 issue "letsencrypt.org" 0 issue "pki.goog" 300s 64.8 ms 10.89.0.1
19:47:25 SOA ns-cloud-e1.googledomains.com cloud-dns-hostmaster.google.com 1 21600 3600 2592… 21600s 20.3 ms 10.89.0.1
19:47:25 TXT
5 records google-site-verification=qvibgBDBD_1VeFXvgduqw1cm…
google-site-verification=qvibgBDBD_1VeFXvgduqw1cmDeMpAS_qBCZCFauYduk google-site-verification=mJdpiJi2GyNG9nz7sctCXgJnzDHzdFzfhOqTTDuMR0s google-site-verification=3oHHTSOKrjE9J8SIvyj3gUxEtDjmr5oNZ-DbB271vpM google-site-verification=eYE-BIP9BY8VZCUI_r8sJi7qjRVtxyRQSlbZmeVVlzE google-site-verification=eqtrduRyMRS8TuoUEuYMF-u9_IDRMd1In6T6E1gTchU
300s 19.5 ms 10.89.0.1
19:47:25 NS ns-cloud-e3.googledomains.com ns-cloud-e4.googledomains.com ns-cloud-e1.googledomains.com ns-cloud-e2.googledomains.com 21600s 20.4 ms 10.89.0.1
19:47:25 MX 5 alt2.aspmx.l.google.com 10 alt3.aspmx.l.google.com 10 alt4.aspmx.l.google.com 5 alt1.aspmx.l.google.com 1 aspmx.l.google.com 300s 28.8 ms 10.89.0.1
19:47:25 AAAA 2001:4860:4802:32::15 2001:4860:4802:38::15 2001:4860:4802:34::15 2001:4860:4802:36::15 300s 19.9 ms 10.89.0.1
19:47:25 A 216.239.36.21 216.239.32.21 216.239.38.21 216.239.34.21 300s 41.8 ms 10.89.0.1
Open Ports 10
Open Ports
10
IPs Scanned
10
Port Protocol Service IP Address Status Latency Banner
80 TCP http 216.239.32.21 Open 7.7 ms
80 TCP http 2001:4860:4802:38::15 Open 41.0 ms
80 TCP http 216.239.34.21 Open 6.7 ms
80 TCP http 2001:4860:4802:32::15 Open 7.8 ms
80 TCP http 216.239.36.21 Open 7.6 ms
443 TCP https 216.239.36.21 Open 9.5 ms
443 TCP https 216.239.32.21 Open 7.5 ms
443 TCP https 2001:4860:4802:38::15 Open 7.8 ms
443 TCP https 2001:4860:4802:32::15 Open 39.8 ms
443 TCP https 216.239.34.21 Open 6.4 ms
Lighthouse Report
1 hour, 14 minutes ago
Mobile screenshot of go.dev
Mobile viewport
47
Performance
88
Accessibility
93
Best Practices
85
SEO
90–100 Good 50–89 Needs Work 0–49 Poor
Core Web Vitals: Failed
LCP
6740 ms
Poor
TBT
971 ms
Poor
CLS
0.000
Good
FCP
3027 ms
Poor
SI
4896 ms
Needs Work
TTFB
76 ms
Good
Score Audit Category
0
Browser errors were logged to the console
best-practices
0
Minimize main-thread work
6.3 s
performance
0
Reduce JavaScript execution time
2.1 s
performance
0
Preconnect to required origins
Est savings of 320 ms
performance
0
Reduce the impact of third-party code
Third-party code blocked the main thread for 1,040 ms
performance
0
Largest Contentful Paint element
6,740 ms
performance
0
Background and foreground colors do not have a sufficient contrast ratio.
accessibility
0
Image elements do not have `[alt]` attributes
accessibility seo
0
Links do not have a discernible name
accessibility
0
Eliminate render-blocking resources
Est savings of 1,200 ms
performance
0
Reduce unused CSS
Est savings of 20 KiB
performance
0
Reduce unused JavaScript
Est savings of 245 KiB
performance
0
Issues were logged in the `Issues` panel in Chrome Devtools
best-practices
0
Links do not have descriptive text
1 link found
seo
0
Use efficient cache lifetimes
Est savings of 339 KiB
performance
0
Font display
Est savings of 30 ms
performance
0
Forced reflow
performance
0
LCP request discovery
performance
0
Network dependency tree
performance
0
Render blocking requests
Est savings of 1,350 ms
performance
7
Largest Contentful Paint
6.7 s
performance
23
Max Potential First Input Delay
360 ms
performance
28
Total Blocking Time
970 ms
performance
49
First Contentful Paint
3.0 s
performance
50
Ensure text remains visible during webfont load
performance
50
Image elements do not have explicit `width` and `height`
performance
50
Serve static assets with an efficient cache policy
57 resources found
performance
50
Defer offscreen images
Est savings of 29 KiB
performance
50
Minify CSS
Est savings of 5 KiB
performance
50
Minify JavaScript
Est savings of 3 KiB
performance
50
Serve images in next-gen formats
Est savings of 74 KiB
performance
50
Properly size images
Est savings of 106 KiB
performance
50
Avoid serving legacy JavaScript to modern browsers
performance
50
Improve image delivery
Est savings of 106 KiB
performance
53
Time to Interactive
7.0 s
performance
65
Speed Index
4.9 s
performance
Desktop screenshot of go.dev
Desktop viewport
92
Performance
88
Accessibility
93
Best Practices
85
SEO
90–100 Good 50–89 Needs Work 0–49 Poor
Core Web Vitals: Passed
LCP
1048 ms
Good
TBT
181 ms
Good
CLS
0.019
Good
FCP
857 ms
Good
SI
1010 ms
Good
TTFB
63 ms
Good
Score Audit Category
0
Browser errors were logged to the console
best-practices
0
Background and foreground colors do not have a sufficient contrast ratio.
accessibility
0
Image elements do not have `[alt]` attributes
accessibility seo
0
Links do not have a discernible name
accessibility
0
Eliminate render-blocking resources
Est savings of 370 ms
performance
0
Reduce unused JavaScript
Est savings of 246 KiB
performance
0
Issues were logged in the `Issues` panel in Chrome Devtools
best-practices
0
Links do not have descriptive text
1 link found
seo
0
Use efficient cache lifetimes
Est savings of 351 KiB
performance
0
Font display
Est savings of 300 ms
performance
0
Forced reflow
performance
0
LCP request discovery
performance
0
Network dependency tree
performance
0
Render blocking requests
Est savings of 410 ms
performance
50
Ensure text remains visible during webfont load
performance
50
Image elements do not have explicit `width` and `height`
performance
50
Serve static assets with an efficient cache policy
57 resources found
performance
50
Defer offscreen images
Est savings of 29 KiB
performance
50
Minify CSS
Est savings of 5 KiB
performance
50
Minify JavaScript
Est savings of 3 KiB
performance
50
Reduce unused CSS
Est savings of 19 KiB
performance
50
Serve images in next-gen formats
Est savings of 74 KiB
performance
50
Properly size images
Est savings of 106 KiB
performance
50
Avoid serving legacy JavaScript to modern browsers
performance
50
Improve image delivery
Est savings of 106 KiB
performance
84
Total Blocking Time
180 ms
performance
85
Max Potential First Input Delay
150 ms
performance
Technology Stack 9 detected
HTTP/2
HTTP/3 (QUIC)
9
Technologies
Analytics 1
Google Tag Manager
70%
GTM script
CMS 1
Medium
70%
Medium domain
Email 1
Google Workspace
85%
MX record: 5 alt2.aspmx.l.google.com
Library 1
jQuery
70%
jQuery script
Security 2
CSP
90%
Content-Security-Policy present
HSTS
90%
HSTS header present
Service 1
Google Fonts
70%
Google Fonts CSS
Social 1
Twitter Cards
70%
Twitter Card meta
Verification 1
Google Search Console
85%
TXT verification: google-site-verification=eqtrduRyMRS8TuoUEuYMF-u9_IDRMd1In6T6…
Crawl Configuration
robots.txt No sitemap
robots.txt 0 disallow · 1 allow · 1 agent
User-Agent Directive Path / Value
* Allow /
User-agent: *
Allow: /
Sitemap

No sitemap discovered.
Checked /robots.txt, /sitemap.xml, and /sitemap_index.xml

Active IP Addresses
IP Address Version Reverse DNS CIDR Country City ASN First Seen Last DNS Hits Misses Uptime % Avg Latency
2001:4860:4802:32::15 IPv6 any-in-2001-4860-4802-32--15.1e100.net 2001:4860:4802::/48 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 29.5 ms
2001:4860:4802:34::15 IPv6 any-in-2001-4860-4802-34--15.1e100.net 2001:4860:4802::/48 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 18.9 ms
2001:4860:4802:38::15 IPv6 any-in-2001-4860-4802-38--15.1e100.net 2001:4860:4802::/48 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 29.2 ms
2001:4860:4802:36::15 IPv6 any-in-2001-4860-4802-36--15.1e100.net 2001:4860:4802::/48 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 18.9 ms
216.239.36.21 IPv4 any-in-2415.1e100.net 216.239.36.0/24 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 7.3 ms
216.239.34.21 IPv4 any-in-2215.1e100.net 216.239.34.0/24 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 7.8 ms
216.239.38.21 IPv4 any-in-2615.1e100.net 216.239.38.0/24 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 7.5 ms
216.239.32.21 IPv4 any-in-2015.1e100.net 216.239.32.0/24 US AS15169 Google LLC 2026-04-11 19:47 2026-04-11 21:53 3 0 100.0% 7.8 ms
Discovered Sub-domains 27
Wordlist Brute-force 6 Certificate Transparency 21

1. admin.go.dev
2. blog.go.dev
3. dev.go.dev
4. learn.go.dev
5. staging.go.dev
6. vuln.go.dev

beta.pkg.go.dev 1 hour, 4 minutes ago
build.go.dev 1 hour, 4 minutes ago
dev-pkg.go.dev 1 hour, 4 minutes ago
dev-prober.go.dev 1 hour, 4 minutes ago
dev-telemetry-worker.go.dev 1 hour, 4 minutes ago
dev-telemetry.go.dev 1 hour, 4 minutes ago
dev-worker.go.dev 1 hour, 4 minutes ago
ecosystem.go.dev 1 hour, 4 minutes ago
exp-worker.go.dev 1 hour, 4 minutes ago
pkg.go.dev 1 hour, 4 minutes ago
play.go.dev 1 hour, 4 minutes ago
prod-prober.go.dev 1 hour, 4 minutes ago
prod-worker.go.dev 1 hour, 4 minutes ago
staging-learn.go.dev 1 hour, 4 minutes ago
staging-pkg.go.dev 1 hour, 4 minutes ago
staging-prober.go.dev 1 hour, 4 minutes ago
staging-worker.go.dev 1 hour, 4 minutes ago
talks.go.dev 1 hour, 4 minutes ago
telemetry-worker.go.dev 1 hour, 4 minutes ago
telemetry.go.dev 1 hour, 4 minutes ago
tour.go.dev 1 hour, 4 minutes ago
Recent HTTP Checks (24 h)
Total Checks
3
Success Rate
100%
Avg Response
199 ms
Min / Max
189 / 217 ms
Recent Checks
19:47 21:53
Time Status Code Response Agent Error
21:53:29 UP 200 190 ms prod-local
20:50:14 UP 200 217 ms prod-local
19:47:25 UP 200 189 ms prod-local
Incident History

No incidents recorded — all clear!