
JSFiddle
CodeSandbox
GitHub
replit
VS Code
Pastebin.com
JS Bin
A front end web development playground.

GitHub Codespaces
Gitpod
replit
Coder
CodeSandbox
Cloud AI workstation that keeps your coding agents running after you disconnect.
Which is more popular?
Based on our record, CodePen seems to be more popular. It has been mentioned 513 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | codepen.io | holycode.cloud |
| Pricing | — | |
| Company | — | Startup from the United States · 1 - 9 employees · 2026 |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of CodePen yet.
HolyCode Cloud is a cloud AI workstation with 60+ tools already installed, built for running AI coding agents unattended. Hand off a task, close your laptop, and the work continues. Processes, files and terminal scrollback survive the disconnect, and the machine suspends when idle and resumes in...
What each product offers, as listed by its team.


Possible disadvantages
No features have been listed yet.
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
No analysis of HolyCode yet.
Walkthroughs and reviews on video.
What Is Codepen?
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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing CodePen and HolyCode.
HolyCode's answer:
The machine does not stop when you do. Most cloud dev environments are containers with an idle timer that reclaims them when nobody has typed for a while, which is exactly what a working unattended agent looks like to a timer. Here the workspace is a real VM with a persistent disk. Hand an agent a four-hour task, close your laptop, and the processes, files and terminal scrollback are still there when you come back. It suspends when idle and resumes in about a second, so always-on does not mean always-billing.
HolyCode's answer:
Three practical differences. First, nothing gets reclaimed for idleness, so long unattended agent runs actually finish. Second, every tier includes the full toolset. Tiers differ only by CPU, RAM and disk, so paying more buys horsepower rather than unlocking features. Third, you bring your own Anthropic, OpenAI or Gemini key and the provider bills you directly, with no markup on tokens.
Where it is not the right choice: if you want a free tier to try, there isn't one, because every account is a real VM that costs money from the first minute. There is a 7-day refund instead.
HolyCode's answer:
Developers running AI coding agents on real work rather than demos. Typically people who already pay for Claude, Codex or Gemini and have hit the point where the bottleneck is not the model but the machine underneath it. Many have tried tmux on a VPS and got tired of maintaining the VPS.
HolyCode's answer:
It started as an open-source Docker image for running coding agents with persistent state, which is still free and maintained at github.com/CoderLuii/HolyCode. The most common feedback was that persistence mattered most: sessions, settings and progress surviving a rebuild rather than starting over each time. The hosted version is that same image on a machine someone else maintains.
HolyCode's answer:
Fly.io machines with persistent volumes for the workspaces, Docker and Debian for the image, ttyd for the browser terminal, Node and React for the interface, and Cloudflare for the site and control plane.
Share your experience with using CodePen and HolyCode. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


Codepen is a social network for developers to show off their work, ask and answer questions, and exchange ideas. It's like a Reddit for coding and design, with a large community of talented web developers.
Codepen is a social development environment that allows developers to showcase their work and experiment with HTML, CSS, and JavaScript in a collaborative space. Codepen’s focus on visual and interactive development...
Codepen is a social development environment for front-end designers and developers. Build and deploy a website, show off your work, build test cases to learn.
We have no reviews of HolyCode yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


> I vividly remember IE and many hacks to have css elements properly working in it… The common advice now is to only use CSS that is supported in the last two major versions of each major browser. You can check any css property's support... - Source: Hacker News / 2 months ago
Thank you, heartfelt... For sharing an artwork, a miracle! Just in case, have you considered publishing the work at platforms as CodePen, where genius Artists/People express their art, too, as you?: // https://codepen.io/. - Source: Hacker News / 3 months ago
Embed on DEV: If you prefer CodePen embed, create a Pen with that HTML and add to the post as: {% codepen https://codepen.io//pen/ %}. - Source: dev.to / 12 months ago
Tracking HolyCode since Aug 2026.
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