spa: the good parts

Next.js@nextjs.org · last mo.

So, we're borrowing a trick from single-page apps. Next.js now prefetches one reusable shell per route and caches it on the client, instead of a separate request per link. A click renders the prefetched shell instantly while the rest of the page streams in from the server.

I wrote about this in my newsletter this week. www.joshwcomeau.com/email/wham-l...

The elephant in the room • Josh W. Comeau

Friendly tutorials for developers. Focus on React, CSS, Animation, and more!

joshwcomeau.com

🎉 Registration is now open for my latest course, Whimsical Animations! This course will teach you everything you need to know to design and build stunning, creative animations and interactions. It’s time to make the web less generic and boring! 😄

Whimsical Animations

Learn how to create charming interactions and delightful touches using the magic of CSS, JavaScript, SVG, and Canvas. I’m sharing all my tricks in this one!

whimsy.joshwcomeau.com

✨ Tomorrow’s the day! After 18+ months of work, Whimsical Animations will be releasing to the public. 😄 I just sent a FAQ about the course to everyone on my newsletter. If you have any questions about it, they might be answered here:

Tomorrow’s the day! • Josh W. Comeau

Friendly tutorials for developers. Focus on React, CSS, Animation, and more!

joshwcomeau.com

This Week In React 278 ⚛️ - React Email - TSRX - ESLint plugin - Rspack RSC - TanStack Store / Blog - Hook Form 📱 - Vision Camera - Expo - Nano Icons - ExecuTorch - Argent - Audio API - RNSec - CSS 🍿 Read thisweekinreact.com/newsletter/278 ✍️ @piaskowyk.bsky.social @filip-solecki.bsky.social

Next.js 16.2 just gave AI agents a Browser next-browser lets an agent inspect your running app, not just the code LLMs can’t open DevTools, see skeleton states, or check the network tab Ready for more Next.js? 🎁 Download a FREE Cheatsheet ↓ dub.sh/nextjs-mist...

My upcoming animations course has a few open-ended exercises where the goal is to experiment with the APIs we’ve learned about. Some of the things people are coming up with are legitimately beautiful, like this delightful example from @miksevigny.com 💯

Ever had an Agent start a New Dev Server when it’s already running? Next.js 16.2 stops this with one quick change 🧠 The Fix → create a .next/dev/lock file Aka never ever try to start a new dev server when one is already running

Is Next.js Really Dead? Think again Next.js powers 55% of YC W26 company websites i.e. 111 out of 200 The next closest? Vite/React at 37 sooo, If you're learning Next.js, you're in good company 😉 🎁 Want to dive deeper? Grab a FREE Next.js Cheatsheet on 29 Common Mistakes dub.sh/nextjs-mist...

Stop trusting AI to use the right Next.js patterns Your AI writes code for Next 13 instead of 16 Next.js 16.2 fixes this with one file 🔥 → create-next-app now generates agents.md → Tells AI to read version-matched Next.js docs locally → The docs live in node_modules/next/dist/docs as markdown

Stop calling `redirect()` inside a try/catch in Next.js `redirect()` intentionally throws an internal error to trigger the redirect. Put it in a try block and your catch will swallow it, no redirect Fix: move `redirect()` outside the try/catch FREE cheatsheet: 29 mistakes dub.sh/nextjs-mist...

You're debugging a Next.js error at midnight and AI keeps hallucinating 😖 Stuck on Lesson 16? sure you can ask AI but there is no better feeling than to review the comments & see if others hit the exact same bug in the exact same project Well, I just shipped comments! → dub.sh/nextjscours...

Stop using window or document inside your Next.js server components 💡What happens Server components don't have access to window, document, or events 🧠 The Fix So extract that logic into a separate client component and keep the rest server-rendered 🎁 FREE Cheatsheet here dub.sh/nextjs-mist...

Last week's Snack: Stop putting Auth in Middleware ⚡🍿 🚀 Tanstack Start SSR throughput jumps 5x after profiling hot paths 🧠 How not to overuse useEffect, what to use instead ⚡ OpenAI drops GPT-5.4 mini & nano → 2x faster, built for subagents and more dub.sh/lVxxmtV

Stop wrapping ThemeProvider directly in your Next.js Layout What happens ✔️ Entire component tree becomes client-rendered ✔️ Server components stop working ✔️ You lose App Router performance benefit ✅ Fix Use the "children" pattern 🎁 FREE Cheatsheet here dub.sh/nextjs-mist...

Last week's Snack: Stop putting Auth in Middleware ⚡🍿 🤖 @tanstack.com AI Openrouter → One API, 300+ AI models ✨ @shadcn.com v4 CLI just dropped → One command restyled your whole design system ⚡ @astrodotbuild.com Astro 6.0 → Fonts, better SSR & Rust compiler and more dub.sh/zQBEV3F

Stop placing your Suspense boundary in the wrong spot in Next.js Suspense only shows a fallback after render. If you `await` in the same component, it blocks first ✅ Put async work in a child, then wrap that child with Suspense one level up 🎁 Download a FREE Cheatsheet here dub.sh/nextjs-mist...

Every Server Action in Next.js is a public API endpoint That means anyone can find the URL in DevTools and call it directly. Treat them like API routes and secure them by: → Authentication → Input validation → Authorization 🎁 Want more? Download the FREE Cheatsheet dub.sh/nextjs-mist...

Is your Next.js app feeling sluggish or taking forever to load? Try the experimental Bundle Analyzer, an X-ray for your app Get an interactive Treemap of your JS bundles → Find the culprits 🎁 Free lessons: dub.sh/how-does-ne...

Stop wrapping your entire Next.js page in "use client" Just because ONE component in the page needs interactivity You'll turn the entire page into client components Solution: ✔️ Extract only the interactive piece into its own client 🎁 Want more? Download the FREE Cheatsheet dub.sh/nextjs-mist...

Your AI agent keeps making the same React mistakes over and over You need to use Skills Skills are the NPM for AI Agents You install best practices like you would a npm package → One command and your agent follows 10+ years of patterns instead of guessing 🍿 Full breakdown: dub.sh/npm-for-ai-...

This ONE concept is killing your app's performance Every component is a Server Component by default in Next.js You're shipping Client side JS when you don't need to 🎁 Here's a FREE lesson covering, ✔️ Server Components basics ✔️ Their purpose ✔️ When to opt out → dub.sh/server-comp...

Running multiple AI agents on the same project? The moment one switches branch, the other breaks Thats because Git only allows one branch checkout at a time The fix? → 𝗚𝗶𝘁 𝗪𝗼𝗿𝗸𝘁𝗿𝗲𝗲𝘀 ⚡ Each agent gets its own folder, its own branch, same repo 🍿 Full breakdown: dub.sh/git-worktree

🚀 @kulkarniankita.com is speaking at #ReactParis 2026 Discover the #toolkit and #architecture for creating #AI Minions; autonomous #agents that fetch data, trigger workflows, and scale like real teammates in #nextjs apps... Learn more 👉🏼 React.Paris #conference #speaker #reactjs

How I realized the workplace is toxic youtu.be/_-Tj3bPSYCI...

I've had an execeptionally tough year. I have no income or health insurance, and could really use your help finding my next paid project. 💜 semanticfish.com/2025-year-in... Open to front-end, full-stack, design system, & accessibility projects. 10+ years experience. Many more details in post!

2025: Year in Review | Semantic Fish Creative Group

This post gets personal about my experiences this year with grief, loss, health emergencies, and being disabled & working in accessibility in the US.

semanticfish.com

Writing my last newsletter of the year!

@kevinpowell.co is only 4K subs away from 1M subs, let’s support him. If you don’t subscribe, please do as he is the best and I learned a lot of CSS tricks and tips over the years! Subscribe here 👇 youtube.com/@kevinpowell

Kevin Powell

Helping you learn how to make the web, and make it look good while you're at it. With weekly videos and shorts, I'll be bringing you How Tos and Tutorials, as well as simple tips and tricks, with a b...

youtube.com

@kevinpowell.co is only 4K subs away from 1M subs, let’s support him. If you don’t subscribe, please do as he is the best and I learned a lot of CSS tricks and tips over the years! Subscribe here 👇 youtube.com/@kevinpowell

Kevin Powell

Helping you learn how to make the web, and make it look good while you're at it. With weekly videos and shorts, I'll be bringing you How Tos and Tutorials, as well as simple tips and tricks, with a b...

youtube.com

a mistake I see constantly: leaders go quiet when something went wrong in the absence of the real story, people will try to piece the story together from incomplete information a story always gets told. rumors are usually worse than the truth. be vulnerable: own it so you have a chance to recover