Vivari – Open-Source WebContainer for Node, Bun, and Python

In plain words

Vivari is an open-source WebContainer that runs Node, Bun, and Python code in the browser. Designed for developers, it enables serverless code execution without external infrastructure. The tool supports multiple runtime environments, making it useful for prototyping, testing, and building web-based development environments. Being open-source, users can inspect and modify the code to fit their needs.

written from the facts on this page · September 2026

• 
  BunDec 2025 · bun.com · ▲295

  A fast JS runtime Node.js replacement with built‑in tools

• 
  I built a WASI playground for running CLI binaries in the browser2022 · runno.dev · ▲115

  Run WebAssembly made for outside the browser, inside the browser.

• 
  WebContainer API2023 · webcontainers.io · ▲121

  Dev environments, in your web app

• 
  Open Interpreter2023 · openinterpreter.com · ▲182

  Control your computer with natural language

• 
  KeystoneMar 2026 · github.com · ▲125

  We kept hitting the same wall: you clone some arbitrary repo and just want it to run without any configuration work. So we built Keystone, an open source tool that spins up a Modal sandbox, runs Claude Code inside it, and produces a working .devcontainer/ config (Dockerfile, devcontainer.json, test runner) for any git repo. We build on the dev container standard, so the output works with VS Code and GitHub Codespaces out of the box. Main use cases: reproducible dev/CI environments, self-describing repos, and safely sandboxed coding agents. Our goal is to encourage all repos to…

• 
  Node.JS in the Browser – An Open-source Alternative to WebContainersAug 2026 · developer.puter.com · ▲6

  This is a Node.js compatible runtime in the browser. It supports CLI apps, Vite, and some agents (like Pi Agent) as well. Some notes: - This runs all code in a web worker using the host javascript runtime with rewrites for module loading and AsyncLocalStorage support using Oxc compiled to WASM. - Most of the libraries are bundled straight from Node.js upstream with light overrides where needed, ensuring compatibility. Libraries were only reimplemented where really needed - Despite having great integrations with the Puter desktop and APIs, this can be used completely seperately with OPFS…

• 
  /dev/null▲494

  a social network for devs

  Dev tools · 4d ago · dev-null.sh

• 
  Run full iOS 16.5 firmware on Android Devices▲474

  Contribute to oosexgang/hackios-xnu-kernel development by creating an account on GitHub.

  Dev tools · 23h ago · github.com

• 
  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 · 29d 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 · 27d ago · github.com

• 
  OpenBot▲362

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

  Dev tools · 24d ago · openbot.run

• 
  Talanoa▲346

  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 · 22d ago · talanoa.email

• IR
  I replaced a $120k bowling center system with $1,600 in ESP32s▲2,935

  I might be the only SRE on Earth with his own bowling center. It's a more in-depth gig than you'd think. My family and I bought an abandoned 8-lane bowling center in the rural mid-west. In our small town there weren't many recreation options for families. You've heard of a food desert? This is an R&R desert. It had been abandoned for a good reason. The roof leaks, the electrical system was constantly surging, and my 70-year-old bowling equipment (still) doesn't work perfectly. The system that keeps your score is particularly interesting to me. It's the thing you watch during your game, but…

  Life & fun · Jul 2026

• 
  Elevators▲1,680

  How elevators push your buttons

  Life & fun · Jul 2026 · john.fun

• 
  18 Words▲1,160

  Play 18 Words, the free daily word puzzle. The official home is 18words.com. Tap Play now to open today

  Life & fun · Jul 2026 · 18words.com

• BA
  Bento - An entire PowerPoint in one HTML file (edit+view+data+collab)▲1,033

  Over the past few months, our team has been building more and more slidedecks using web frontend technologies with coding harnesses like Claude Code, but a common complaint is to make even small edits we need to edit the code either manually or via the harness. To avoid this loop, I ended up creating Bento, a single HTML file with everything you need in a slide tool including animations and shared editing. There's no install or cloud login, everything works offline. The default deck is around 560 KB and it doesn't need to fetch anything once you got it. Open it in a browser and then you can…

  Dev tools · Jul 2026 · bento.page

• 
  Getting GLM 5.2 running on my slow computer▲937

  A few days ago I found myself trying out GLM 5.2 and was really positively impressed. The capabilities and security I was getting from this LLM are similar to those I've gotten from models like Claude or GPT, and this really surprised me. But then I thought, "I wonder how it would work on a normal computer like mine," and above all, "I wonder if it would work without going into OOM on a computer like mine." So I started working with the help of agents to test this possibility. I started converting the model to int4, understanding MTP usage, and if possible implementing DSA for long context.…

  AI · Jul 2026 · github.com

• 
  OpenSEO▲928

  Hello! For the last 2 months, I've been building OpenSEO. It's a user friendly UI wrapping the DataForSEO API which has high quality SEO data for keywords, backlinks, AI SEO and competitor research. Instead of paying $100+ per month, you buy DataForSEO credits and pay only for usage. The coolest thing about the project so far has been hearing about what people are building on top of it. People are using coding agents to quickly integrate with Google Search Console, Google Ads and building their own AI SEO and reporting features. Many were already building their own custom solutions around…

  Dev tools · Jul 2026 · openseo.so