
CodePen
CodeSandbox
replit
Pastebin.com
JS Bin
VS Code
GitHub
Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.

Port Monitor
MacMonitor
Open Ports
See what's exposed. The macOS menu bar app that shows every open port, tunnel, VPN, and container — before it's a problem.

Which is more popular?
Based on our record, JSFiddle seems to be more popular. It has been mentioned 204 times since March 2021.
Website, pricing, platforms and company facts side by side.
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|---|---|---|
| Website | jsfiddle.net | bosun.dev |
| Pricing | — | |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of JSFiddle yet.
Bosun is a native macOS menu bar app that shows you everything your Mac has open to the network, right when you need it, with no Terminal digging required. It runs lsof in the background to list every listening port, then goes further than a simple port scanner: it maps each port to the process...
What each product offers, as listed by its team.


Possible disadvantages
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
Overall verdict
Why this product is good
Recommended for
Walkthroughs and reviews on video.
Dashboard JSFiddle Online JavaScript Editor jQuery, Angular, Backbone, Underscore, Knockout, Y
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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing JSFiddle and Bosun.dev.
Bosun.dev's answer:
Swift 5.9+, SwiftUI + AppKit (NSStatusItem), lsof for port scanning, Sparkle for auto-updates, Polar for licensing/payments. No Electron, no third-party dependencies beyond Sparkle.
Bosun.dev's answer:
Developers who run local dev servers, Docker containers, and tunnels (ngrok/Cloudflare) daily and need instant visibility into what's bound to which port, without opening Terminal or Activity Monitor.
Bosun.dev's answer:
Bosun is the only menu bar tool that unifies port scanning with network context: it maps ngrok/Cloudflare tunnels, native VPN status, Docker containers, and SSH -L forwards to the process actually holding each port, then lets you kill it in one click. Most alternatives only do one of those things.
Bosun.dev's answer:
iStat Menus monitors the system but not tunnels or containers. Little Snitch blocks connections but doesn't show you what's already running. Seeports comes closest (port scanning for Docker/K8s/dev servers) but lacks tunnel and VPN detection. Bosun covers all of it natively, with zero third-party dependencies, no Electron overhead, and a one-time price instead of a subscription.
Bosun.dev's answer:
Built out of a personal need: constantly losing track of which local dev server, Docker container, or forgotten tunnel was holding a port, and resorting to lsof in Terminal every time. Bosun turns that into a native, always-visible menu bar view.
Share your experience with using JSFiddle and Bosun.dev. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


Test your javascript, CSS, HTML or coffeescript online with jsfiddle code editor. Jsfiddle – code playground.
JSFiddle cannot be used to host code on your server. The code has to be on JSFiddle and is public all the time.
What is missing from JSFiddle is live previews. You have to basically refresh the page by clicking on the play button. And compared to other playgrounds, JSFiddle is probably the slowest. Another slightly frustrating...
We have no reviews of Bosun.dev yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


Https://jsfiddle.net/ used to be also very popular, I see that it is still available, but haven't used it in a while. Which other alternatives do people use now days? - Source: Hacker News / 2 months ago
Coding is like learning a new language—you must practice by writing code, not just reading about it. Use free online editors like CodePen, JSFiddle, or Replit to experiment. - Source: dev.to / about 1 year ago
As you embark on these projects, take your time to familiarize yourself with HTML tags and CSS properties. Use online tools like CodePen or JSFiddle to experiment with your code and visualize your results. - Source: dev.to / over 1 year ago
Tracking Bosun.dev since Jul 2026.
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Code, create, andlearn together. Use our free, collaborative, in-browser IDE to code in 50+ languages — without spending a second on setup.
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Manage, browse and kill open ports on your Mac.
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