Rank #1,292Updated November 10, 2026
codepen.io
CodePen – Online Code Editor For Building & Deploying Websites
The site runs on Ruby on Rails, Next.js, React and 7 other technologies. Its email security grade is D. Its SSL certificate is issued by Google Trust Services and is valid for 89 more days.
- Domain age
- —
- Technologies
- 10
- Email security
- D
- SSL days left
- 89
DNS records
| Type | Value | TTL |
|---|---|---|
| A | 104.16.163.32 | 2 |
| A | 104.16.147.32 | 2 |
| MX | aspmx.l.google.com 1 | 300 |
| MX | alt1.aspmx.l.google.com 5 | 300 |
| MX | alt2.aspmx.l.google.com 5 | 300 |
| MX | aspmx2.googlemail.com 10 | 300 |
| MX | aspmx3.googlemail.com 10 | 300 |
| NS | albert.ns.cloudflare.com | 84893 |
| NS | kristin.ns.cloudflare.com | 84893 |
| TXT | v=spf1 include:s43465759.fdmarc.net ~all | 300 |
| TXT | google-site-verification=ee6yZSYLRMH7NdG8DSox4-fH0btH7GdMbMyY7zHenxY | 300 |
| AAAA | 2606:4700::6810:9320 | 55 |
| AAAA | 2606:4700::6810:a320 | 55 |
Technology stack
Advertising
CDN
Hosting
Security
Web framework
Analytics and advertising IDs
google_adsense:ca-pub-5381196231596750SSL certificate
| Valid | Valid |
|---|---|
| Issuer | US, WE1, Google Trust Services |
| Expires | February 7, 2027 |
| Days remaining | 89 |
| Protocol | TLSv1.3 |
| Names | codepen.io, *.codepen.io |
Email security
DScore 64/100 across SPF, DMARC, DKIM, MTA-STS and BIMI.
- warnNo DKIM key found at common selectors (google, selector1, selector2, default, k1, k2, s1, s2, ...). DKIM may still use a custom selector we cannot guess.
- warnNo MTA-STS: mail sent to you can be downgraded to an unencrypted connection.
- warnNo TLS-RPT record, so you won't hear about failed encrypted deliveries.
- goodSPF record found.
- goodSPF ends with ~all: servers you have not listed are marked as suspicious (soft fail).
- goodDMARC policy is quarantine: failing mail goes to spam. Move to p=reject for full protection.
- goodDMARC aggregate reports are sent to mailto:[email protected].
- good5 MX record(s) found. Mail is handled by Google Workspace.
- goodBIMI record found: supporting inboxes can show your brand logo.
Homepage metadata
| Title | CodePen – Online Code Editor For Building & Deploying Websites |
|---|---|
| Description | Build, share & learn with CodePen 2.0, the best community for developers with an all new online code editor featuring a file system, compiler, realtime & async collaboration, deployment, and more. |
| Language | en |
| Indexable | Yes |
| Word count | 698 |
About codepen.io
What technology does codepen.io use?
We detected 10 technologies on codepen.io, including Google AdSense, Cloudflare, AWS Elastic Load Balancing, Next.js, React, Node.js.
Does codepen.io protect its email with SPF and DMARC?
codepen.io scores 64/100 (grade D) for email security. No DKIM key found at common selectors (google, selector1, selector2, default, k1, k2, s1, s2, ...). DKIM may still use a custom selector we cannot guess. No MTA-STS: mail sent to you can be downgraded to an unencrypted connection.
What are the name servers of codepen.io?
codepen.io uses albert.ns.cloudflare.com, kristin.ns.cloudflare.com.