Bun 1.3: The Full-Stack JavaScript Runtime — Arriving a few hours after last week’s issue (natch!) Bun 1.3 remains the big news of the past week. Bun is a performance and DX-focused JavaScriptCore-powered runtime which, with v1.3, balances being a drop-in Node.js replacement with becoming a ‘full-stack runtime’ among other exciting developments:
Full‑stack dev server with hot reloading built into Bun.serve
Improved GC with lower idle CPU and memory usage.
Built-in MySQL and Redis clients (alongside Postgres and SQLite).
AI Agents? Meet External Tools — Launching an AI-powered app? Make sure your agent is securely connecting with all of your external tools and APIs. Learn more about how Auth0’s Token Vault can secure your logins and agents so your users aren’t left vulnerable and exposed.
Auth0 sponsor
Announcing Vite+ / VitePlus — Originally announced at last week's ViteConf, Evan shares more details about what this extended, unified Vite-based toolchain (now in ‘early access’) is, and the motivation behind it. Unlike regular Vite, it has a commercial angle but “will be free for individuals, open source projects, and small businesses” as well as “source available.”
Evan You
Node.js v25.0.0 (Current) Released — The latest cutting edge version of Node has arrived with Web Storage enabled by default, JSON.stringify perf improvements, a new --allow-net option in the permission model, built-in Uint8Array base64/hex conversion, and WebAssembly and JIT optimizations.
Rafael Gonzaga
IN BRIEF:
Cloudflare Sandboxes is a new service for running untrusted JavaScript (and Python) code in a safe container-based 'sandbox' environment.
The Remix project's Remix Jam event took place last week, and you can now ▶️ watch the full livestream. If you want to see the reveal and demo of Remix 3, jump to 03:24:30 in the video.
Improving the Trustworthiness of JavaScript on the Web — A look at WAICT (Web Application Integrity, Consistency, and Transparency), an early-stage W3C-backed effort to bring stronger ‘app store-like’ security guarantees to the Web by ensuring the code a browser runs hasn’t been modified by attackers.
Michael Rosenberg (Cloudflare)
▶ Beyond Signals — A half-hour talk from the creator of SolidJS, exploring how signals (once pioneering, now mainstream) are shaping web development, their architectural implications, but why we’re only “at the beginning of the journey” and what comes next.
jsonriver: A Simple, Fast Streaming JSON Parser — A library to parse JSON incrementally as it streams in, such as from a network request or an LLM, returning a sequence of ‘increasingly complete’ values.
Peter Burns (Google)
Kaluma 1.3: A Tiny JS Runtime for the Raspberry Pi Pico 2 — Can a JavaScript runtime squeeze onto an RP2350-based Raspberry Pi Pico 2? Kaluma can, all while offering some Node.js-like niceties. v1.3 is powered by the latest version of JerryScript, a lightweight JS engine for constrained environments.
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📢 Elsewhere in the ecosystem
A roundup of some other interesting stories in the broader landscape:
The React team has shipped v1.0 of React Compiler, a tool for automating the optimization of React apps by way of auto-memoization applied based upon analysis of their code.
Sebastian Lague's ▶️ Simulating Smoke video presents a fascinating look at how you might model and code a fluid simulation to emulate the behavior of smoke. It's not in JavaScript but is mostly math anyway.
With this week's release of Firefox 144, all major browsers now support view transitions, a neat front-end feature.
🐈 Cat cams! Nothing to do with programming, but meow.camera charmed me. You might need to switch cameras to actually find a cat. Not a fan of cats? Check out the Namib Desert for some bigger critters..
▶ Vite: The Documentary — From the same creators of the fantastic ▶️ Node.js, ▶️ Angular and ▶️ React documentaries comes an up to date look at Vite, the build tool that has taken the JavaScript ecosystem by storm in recent years. Many luminaries make an appearance to tell their stories, including Evan You, Rich Harris, and Ryan Carniato. (39 minutes.)
CultRepo
💡 In related news, Vite+ (VitePlus) has appeared, a future, more commercial offering of the Vite toolchain aimed at teams. More news on this next week.
Go from Monolith to Monorepo — Join Mike North for this course on architecting maintainable, fast and light codebases. You'll learn how to refactor a codebase into a TypeScript monorepo using tools like Nx and Lerna — covering dependencies, formatting, linting, performance and more.
Frontend Masters sponsor
Introducing the React Foundation — At React Conf 2025 this week, it was announced that control of React and React Native is to be moved from Meta to an independent foundation supported by the Linux Foundation and initially backed by corporate members including Amazon, Expo, Meta, and Microsoft.
Webster, Carroll, Savona and Alpert
📺 If you'd like to catch up with React Conf, you can now watch the ▶️ day one and ▶️ day two livestream recordings on YouTube.
Next.js 16 Beta – Turbopack support is now stable and the default bundler for Next.js apps, React 19.2 support is also baked in, React Compiler support is now stable, and more.
The Birth of Prettier — The author takes us back ten years to the genesis of Prettier, the popular opinionated, deterministic code formatter he co-created with James Long. Prettier effectively introduced and popularized the practice of fully-automated AST-based code formatting in the JavaScript ecosystem.
The History of Core Web Vitals — Addy tells the story behind Core Web Vitals, a popular set of metrics for measuring Web performance and its impact on user experience.
A roundup of some other interesting stories in the broader landscape:
👍 The Firefox team has put together a way for you to give input on which Interop proposals matter the most to you (above). Go to the Interop Feature Ranking site(GitHub account required) and drag the web platform features that matter most for you to the top.
🖼️ Mirrow is an interesting way to create and animate SVGs using a custom CSS-esque DSL in an attempt to promote SVGs from merely being static assets to something you can manage in a more code-like way. Check out the Mirrow playground to experiment.
We've all heard of vibe coding but Simon Willison wonders if LLMs used properly to produce code that someone confidently stand behind could be considered 'vibe engineering'?
Talking of vibes, Heroku is taking a step into the world of AI-powered app building with Heroku Vibes.
The State of JavaScript 2025 Survey — Each year, Devographics runs an epic survey of as many JavaScript community members as it can and turns the results into an interesting report on the state of the ecosystem – here’s the results from 2024. If you have the time, fill it in, especially as they format it in a way where you can actually learn about stuff as you go.
Devographics
React 19.2 Released — The third release in a year for React, this time introducing new features like <Activity /> (a way to hide and restore the UI and internal state of its children), useEffectEvent, and improvements to Chrome DevTools' performance profiles so you can see more about React’s scheduling and the tree of components it’s working with. Oh, and how about partial pre-rendering?
The React Team
Don’t miss The AI Security Developers Challenge at DevSecCon on Oct 22, 2025 — Participate in the hands-on developer challenge workshop 💻at DevSecCon and get a chance to team up with industry experts from around the globe 🌎. Register for free and walk away with practical tips you can apply directly to your projects 🚀.
The newly relaunched JSConf event returns to Maryland on October 14-16. Tickets are still available and they gave us a JSCONF25NEWSLETTER code which gives a discount. (Note: We have no financial relationship with the event.)
Mastering npx: A Cheatsheet for npm and Node Power Users — You’ve almost certainly used the npx command to easily run a command from an npm package (either local or remote) – it’s easy to use, but npx has a couple of other features and options to keep in mind.
qjs: Run JavaScript in Go using QuickJS and Wazero — A new Cgo-free JavaScript runtime option for integrating JavaScript into apps written in Go. It uses a fork of QuickJS that’s compiled to WebAssembly and then run using Wazero.
Have you ever wanted to program by whistling? Now you can. Velato is a JavaScript-inspired esoteric language designed to be written entirely by whistling and you can give it a go in your browser right now. I struggled with it, but you might have more luck (it doesn't seem to like Safari, for starters).
Velato was built by Daniel Temkin, the author of Forty-Four Esolangs, a new book, published by MIT Press, about an artist's take on creating esoteric programming languages.
AI Code Reviews Meet CLI Coding Agents — CodeRabbit CLI brings instant code reviews directly to your terminal, integrating with Claude Code, Cursor CLI, and other AI agents. While they generate code, CodeRabbit ensures it's production-ready - catching bugs, security issues, and hallucinations before they hit your codebase.
CodeRabbit sponsor
GitHub's Plan for a More Secure npm Supply Chain — In direct response to the recent npm ecosystem supply chain attacks of recent weeks, GitHub’s senior director of security research has outlined steps GitHub is taking, including blocking the upload of packages featuring the patterns of the recent malware, hardening package publication, and promoting the use of trusted publishing.
NPM Security Best Practices — An extensive list of best practices, techniques, and ideas to consider for making your use of the npm packaging ecosystem and its tooling more secure.
JSON is Not JSON Across Languages — If you use JSON to communicate between systems built in different languages, beware. Different libraries with varying opinions can cause “some of the most soul-crushing debugging experiences in software development.”
🤖GitHub Copilot CLI Now in Public Preview — Not content to let Claude Code and OpenAI Codex dominate the CLI-based dev agent scene, GitHub has released a CLI-based version of Copilot, built using Node.
GitHub
TanStack Start v1 Release Candidate — TanStack’s attempt at a full-stack TanStack Router-powered framework has reached a v1.0 release candidate that’s expected to be largely the same as its eventual 1.0 release. “It’s the next chapter in building type-safe, high-performance React apps without the heavy abstractions.”
Cap'n Web: A New RPC System for Browsers and Web Servers — A ‘spiritual sibling’ to Cap’n Proto, an RPC protocol created by one of the same authors. However, Cap’n Web’s underlying serialization is human-readable, focused on integrating well with JS runtimes, and works over HTTP, WebSocket, and postMessage() out-of-the-box.
📊 Billboard.js 3.17.0(above) – The popular charting library adds image label support for charts, label border styling, and dynamic control of label colors.
PythonMonkey 1.3 – Embed the SpiderMonkey JS engine into Python's VM. Now with Python 3.14 support.
pretty-bytes 7.1 – Convert a size in bytes into a human readable equivalent (e.g. 1337 becomes '1.34 kB').
Docusaurus 3.9 – The popular React + MDX-powered content/docs site generator.
Neo.mjs 10.9 – Multi-threaded framework for fast, desktop-like webapps.
Over the past couple of months the esteemed Dr. Axel Rauschmayer has been working on a valuable series of beginner-friendly posts on a range of web development topics, with a heavy focus on JavaScript. He pitches the series as a way to teach people "who have never programmed how to create web apps with JavaScript".
These are all excellent primers/refreshers, and ideal for sharing with those early in their web development journey. Here are some of the highlights so far: