WTF is SWR?

Okay, real talk.

You’re building your sick Next.js app. API routes everywhere. Data here, data there. And you’re tired of juggling useEffect, fetch, isLoading, error states like you’re spinning plates in a circus.

What if I told you there’s a hook that fetches your data, caches it, keeps it fresh automagically—all with 2 lines of code?

Meet SWR.

But wait... why the weird name?

SWR = Stale-While-Revalidate.

Sounds like a cache-control header from the depths of HTTP RFC hell.
But for us mortals, it simply means:

Stale: Serve the cached data first (if any).
While Revalidate: Fetch fresh data in the background.
Update your UI when the fresh data arrives.

This makes your app feel instant while also keeping data fresh. Like that guy who brings old pizza to the table while the fresh one’s in the oven.

Why Should You Care?

No More Boilerplate: Forget about useEffect, fetch, and state management. SWR handles it all.
Automatic Caching: SWR caches your data, so you don’t hit the server every time.
Background Updates: Your data stays fresh without annoying loading spinners.
Error Handling: Built-in error handling. No more try-catch hell.
Optimistic UI: You can update your UI instantly while waiting for the server response

Real-Life Analogy

Imagine this:

You ask your friend:
"Hey, what’s the score of the cricket match?"

He instantly says:
"Last I checked, India was 123/4." (Stale data, but quick!)

Then he pulls out his phone, checks the live score, and updates you:
"Oh wait, they’re 139/5 now." (Revalidated data!)

That’s SWR in action.

The SWR Hook (aka, 2 lines to glory)

import useSWR from 'swr'

const fetcher = (url) => fetch(url).then(res => res.json())

export default function Profile() {
  const { data, error, isLoading } = useSWR('/api/user', fetcher)

  if (isLoading) return <p>Loading user...</p>
  if (error) return <p>Failed to load user</p>

  return <div>Hello, {data.name}!</div>
}

This is it. The magic of SWR.

No more useEffect, no more state management, and no more crying at 2 AM.

Does this actually help performance?

Hell yes!!

Faster Time-to-Interactive (cached stale data shown instantly)
Lower server/API load (because SWR caches like a boss)
No flickering "loading" states on tab switch
Smooth user experience = happy users = happy life

import useSWR from 'swr'

const fetcher = (...args) => fetch(...args).then(res => res.json())

export default function CryptoPrice() {
  const { data, error } = useSWR('https://api.coindesk.com/v1/bpi/currentprice.json', fetcher, {
    refreshInterval: 5000 // refetch every 5s
  })

  if (!data) return <div>Loading price...</div>
  if (error) return <div>Failed to load price</div>

  return <div>BTC Price: ${data.bpi.USD.rate}</div>
}

Now your page updates every 5 seconds without lifting a finger. No sockets. No pain.

When to use SWR?

Client-side data fetching: When you need to fetch data after the initial page load.
Dynamic data: When your data changes frequently and you want to keep it fresh.
User-specific data: When you need to fetch user-specific data that’s not critical for SEO.
Real-time updates: When you want to show real-time data without complex websockets.
Optimistic UI updates: When you want to update the UI instantly while waiting for server confirmation.

When NOT to use SWR?

❌ When you need server-side rendering (getServerSideProps)
❌ When you want static generation (getStaticProps)
❌ When SEO or first-paint data is critical (e.g., blogs, landing pages)
❌ When you need to fetch data on the server before rendering the page

TL;DR

SWR = Stale-While-Revalidate
Client-side data fetching made brain-dead simple
Fast. Cached. Auto-refetching.
Perfect for dashboards, profiles, lists, crypto tickers, live feeds, etc.
Bad for SSR/static needs.

Is it worth it?

Do you like suffering with useEffect and setState?

If no — SWR is your new best friend. (Aura +++)
If yes — enjoy your loading states and weird bugs forever. (Aura -696969)

Thats's SWR in a nutshell. Peace ✌️.

Use SWR and keep you aura glowing.