I've been making JavaScript sandbox alone for 6 years

In plain words

This is a JavaScript sandbox that enables developers to run Node.js packages directly in a web browser with fast performance. It includes a virtual file system and handles import/export resolution. Built over six years by a solo developer, the tool serves approximately 200,000 monthly users and operates on a freemium business model. The creator now works full-time on the project.

written from the facts on this page · September 2026

From the sources

PlayCode is a website where you can type in code and it immediatly shows you what you programmed in a little extra tab. All you need to do is select a programming language or a framework and you can start without needing to set up anything.

Playcode is an AI app builder: describe the site, store, portal, or internal tool you need. Playcode AI builds it, and Playcode Cloud runs it.

Tell Playcode what you need. An AI agent builds it and runs it on our own cloud - real backend, database, and hosting included. Break something? Rewind the whole app, database and all, to a saved moment. One chat, from a one-page site to the software your business runsfrom playcode.io

• IB
  I built an indie, browser-based MMORPG2024 · alpha.reconquer.online · ▲340

  I've been working on an MMORPG that is now in alpha as a solo developer. Here are the major open source technologies that I use: Blender - 3D modeling software for creating the overall environment and every game object. I've gotten a lot of CC and Public Domain assets from https://poly.pizza GLTF - I export assets from blender to the GLTF asset format JSON - I write a JSON config for every game object that describes things like its name, its interactions, its collisions, etc. Node.js exporter - I iterate over the environment and every asset to create a scene hierarchy. I use…

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  Nub – A Bun-like all-in-one toolkit for Node.jsJun 2026 · github.com · ▲277

  Colin here, creator of Nub. I’ve had the general shape of this in mind for years. Nub runs your code with stock `node`, augmented with a `--require` preload hook[0] that adds a transpiler (oxc-powered, packaged as a Node-API add-on), registers a module resolution hook[1], and injects polyfills as needed for APIs like `Worker`, `Temporal`, etc. All purely additive, your code ultimately runs using Node’s actual engine & stdlib implementations. [0] https://nodejs.org/api/cli.html#-require-module [1]…

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  npm i -g hotcellAug 2026 · github.com · ▲97

  Hi HN! Sina here. i wanted to share this open source project (apache 2.0) that i've been working on for the past month or so. it's called hotcell and it lets you create/pause/manage sandboxes on any device (your laptop, linux vm, bare metal). i've tested it against various benchmarks that i found on computesdk (https://www.computesdk.com/benchmarks/sandboxes/) as well as the one shared by dax (cofounder of open code) on twitter recently (link to his original thread and my reply https://x.com/sinasanm/status/2078158598996443346) and…

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  Execute JavaScript in a WebAssembly QuickJS sandbox2024 · github.com · ▲206

  This TypeScript package allows you to safely execute JavaScript code within a WebAssembly sandbox using the QuickJS engine. Perfect for isolating and running untrusted code securely, it leverages the lightweight and fast QuickJS engine compiled to WebAssembly, providing a robust environment for code execution. Features - *Security*: Run untrusted JavaScript code in a safe, isolated environment. - *File System*: Can mount a virtual file system - *Custom Node Modules*: Custom node modules are mountable - *Fetch Client*: Can provide a fetch client to make http(s) calls - *Test-Runner*: Includes…

• SJ
  Sandbox.js - Run user code in a sandboxed environment2012 · engineering.versal.com · ▲31
• CC
  Chunk – Code sandbox for back-end devs2022 · chunk.run · ▲96

  Chunk co-founder here. We spent the last 2 weeks building this to scratch our own itch: As developers, we often have problems that could be solved just by running a few lines of code. Sometimes, running this code on your local machine is fine. But other time, the code need to run automatically reacting to external events or to run continuously, which means, it needs to run on a server somewhere. So now, you have to find a cloud provider, to package or build the code and finally to deploy it. All of that for what could be literally be 4 lines of code. We couldn’t find an easier way to do…

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  /dev/null▲468

  a social network for devs

  Dev tools · 2d ago · dev-null.sh

• 
  Whiteboard (YC W26) – an open-source IDE for thoughtful software design▲423

  open-source IDE for thoughtful software design. Contribute to devdotfast/whiteboard development by creating an account on GitHub.

  Dev tools · 27d ago · github.com

• 
  Reladraw – A diagram language where you decide where to place things▲411

  Contribute to reladraw/reladraw development by creating an account on GitHub.

  Dev tools · 25d ago · github.com

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  OpenBot▲362

  Grok Bot alternative: free, local, open-source, multiplayer

  Dev tools · 22d ago · openbot.run

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  Talanoa▲340

  Hi HN, I’m a fullstack developer, and honestly, I’ve lost count of how many side projects I’ve worked on over the years. But one idea kept coming back to me: a different kind of email client. It first came to me in 2014: “What if we could handle emails more like conversations?” Every year, I’d revisit this concept in my “Build Notes.” Ten years later, no one had built exactly what I had in mind — so I finally decided to do it myself. That’s how Talanoa was born. I wanted something focused on people, not timelines. I was tired of marking messages as unread just to remember to reply later, or…

  Dev tools · 20d ago · talanoa.email

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  CoreSpeed▲332

  One MCP for everything your agents need: apps, memory, tools

  Dev tools · 27d ago · corespeed.io

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  Locofy.ai▲720

  Hey there, I am Honey - Co-founder at Locofy. We, along with other makers, have been building Locofy.ai to help massively accelerate the builders - the designers, developers, product managers & founders, and we're excited to share it today with the HN Community. Locofy.ai simply converts designs into production-ready frontend code for web and mobile apps. It adapts to your preferred design tools, tech stack, and workflows with ease and lets you launch upto 4x faster, while letting designers design the way they want and giving high-quality responsive code that developers love. With this…

  Dev tools · 2022 · locofy.ai

• PO
  Porting OpenBSD Pledge() to Linux▲571

  Life & fun · 2022 · justine.lol

• 
  PocketBase – Open Source realtime backend in one file▲563

  Open Source realtime backend in 1 file. Contribute to pocketbase/pocketbase development by creating an account on GitHub.

  Dev tools · 2022 · github.com

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  ruttl▲552

  Visual & Design Feedback Tool that helps you review design, content and report bugs on websites, applications, PDFs and images.

  Dev tools · 2022 · ruttl.com

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  Pipes puzzle (a.k.a. Net) on a hexagonal grid▲537

  Hello, HN - I wanted to share this puzzle game I made during my vacation. I'm rather fond of the pipes puzzle where your goal is to restore a scrambled network of connections by rotating tiles. It's usually played on a grid of squares and this all started when I decided to make a programmatic solver for that kind of puzzle. Then I realized that with some minor changes the solver could generate new puzzle instances. I thought about what kind of puzzle to make and someone suggested a hexagonal grid. Adapting the generator wasn't too hard but then I had to create a way to play this variant. So…

  Life & fun · 2022 · hexapipes.vercel.app

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  Parsnip – Duolingo for Cooking▲536

  We're building Parsnip to create a "tech tree" of cooking skills that allows anyone to level up on the building blocks of cooking knowledge while tracking their progress over time. It took us a few iterations to figure out the right product; here's the story of our latest pivot: [https://parsnip.substack.com/p/a-new-hope] The goal is to create a personalized way to learn any recipe on the Internet, then use this as a springboard to help home cooks of all levels solve the problem of repeated meal planning in a 10x better way:…

  Work · 2022 · parsnip.ai