Next.js 13 on Vercel: Why Your Data Isn't Updating (Even with cache: 'no-store')
Deploying a Next.js 13 app on Vercel is a smooth experience, but sometimes you encounter a frustrating issue: data from your backend doesn't update on the frontend, despite using cache: 'no-store' in your fetch requests. This can leave you scratching your head, wondering why your app isn't displaying the latest information.
Scenario: Imagine you have a simple Next.js 13 app that fetches blog posts from an API. After deploying the app to Vercel, you update the blog posts on your backend, but the frontend continues to display the outdated posts. This can be particularly frustrating when using cache: 'no-store' in your fetch request, which is designed to explicitly prevent caching.
Let's break down the code:
// pages/blog.js
import React, { useState, useEffect } from 'react';
export default function BlogPage() {
const [posts, setPosts] = useState([]);
useEffect(() => {
const fetchPosts = async () => {
const response = await fetch('/api/posts', {
cache: 'no-store',
});
const data = await response.json();
setPosts(data);
};
fetchPosts();
}, []);
return (
<div>
<h1>Blog Posts</h1>
<ul>
{posts.map((post) => (
<li key={post.id}>{post.title}</li>
))}
</ul>
</div>
);
}
Why is this happening?
The culprit often lies in the way Vercel handles caching:
- Vercel's built-in caching: Vercel implements caching for static content, ensuring efficient delivery. However, this can lead to stale data on the frontend, even with
cache: 'no-store'in your fetch request. - Browser caching: While
cache: 'no-store'tells the browser not to store the response in its cache, the browser may still be caching the request itself, leading to outdated data.
Solutions:
-
Disable Vercel's caching: Vercel provides options to fine-tune its caching behavior. You can disable caching for specific routes in your
vercel.jsonfile or use thevercel-cache-controlpackage to set cache headers directly.// vercel.json { "routes": [ { "src": "/api/posts", "dest": "/api/posts", "headers": { "Cache-Control": "no-cache, no-store" } } ] } -
Force browser refresh: You can force the browser to fetch the latest data by adding a timestamp or unique query parameter to your API endpoint. This effectively tricks the browser into thinking it's a new request.
// pages/blog.js import React, { useState, useEffect } from 'react'; export default function BlogPage() { const [posts, setPosts] = useState([]); useEffect(() => { const fetchPosts = async () => { const response = await fetch(`/api/posts?timestamp=${Date.now()}`, { cache: 'no-store', }); const data = await response.json(); setPosts(data); }; fetchPosts(); }, []); return ( // ... ); } -
Use server-side rendering (SSR) or static site generation (SSG): These features of Next.js allow you to pre-render your pages on the server, fetching the data directly on the server-side. This eliminates the need for client-side fetching and avoids caching issues.
Additional considerations:
- Check your API endpoint: Ensure that your API endpoint is configured to allow CORS (Cross-Origin Resource Sharing) to prevent browser security issues.
- Inspect your browser's cache: Use your browser's developer tools (Network tab) to inspect the requests and responses to identify if caching is occurring.
Conclusion:
Understanding the nuances of caching, both within Vercel and the browser, is crucial when building real-time applications. By implementing the solutions described above, you can effectively prevent caching and ensure your Next.js app always displays the latest data. Remember, a little debugging and testing goes a long way!
