A 304 status code is an HTTP response that tells the browser or crawler that the requested resource has not changed since the last visit. Instead of downloading the content again, the browser uses the cached version, improving performance and reducing server load.
In simple terms, HTTP 304 Not Modified means:
“You already have the latest version — no need to download it again.”What Is a 304 Status Code?
The 304 status code is part of the HTTP 3xx status code family, which deals with how clients should handle requests when content has already been accessed or moved.
Unlike traditional redirects, a 304 response does not send users to a new URL. Instead, it confirms that the cached version of the page or asset is still valid.
Key characteristics:
- No response body is sent
- Uses browser cache
- Improves load speed and bandwidth usage
What Does “304 Not Modified” Mean?
When a browser requests a page, it often sends conditional headers like:
- If-Modified-Since
- If-None-Match (ETag)
If the server determines that the content has not changed, it responds with 304 Not Modified, instructing the browser to load the cached version instead of re-downloading the page.
This is why 304 responses are commonly seen for:
- Images
- CSS & JavaScript files
- Blog pages that haven’t changed
How the 304 Status Code Works (With Example)
Client Request
The browser sends a request like:
If-Modified-Since: Tue, 10 Dec 2024 10:00:00 GMT
Server Response
If no changes are detected:
HTTP/1.1 304 Not Modified
No content is transferred — only headers.
This makes the process fast and efficient.
304 Status Code vs 200 Status Code
| Factor | 200 OK | 304 Not Modified |
|---|---|---|
| Content delivered | Yes | No |
| Uses cache | Optional | Mandatory |
| Page load speed | Normal | Faster |
| SEO impact | Neutral | Positive if configured correctly |
A 304 status code reduces bandwidth usage, while 200 OK delivers fresh content every time.
Is the 304 Status Code a Redirect?
No.
Although it belongs to the 3xx status code category, 304 is not a redirect.
It does not:
- Change the URL
- Pass link equity
- Replace 301 or 302 redirects
However, it is still grouped under redirection status codes because it instructs the browser how to handle the request flow.
304 Status Code and SEO Impact
From an SEO perspective, 304 status codes are generally beneficial when used correctly.
Positive SEO Effects
- Reduces crawl budget waste
- Improves page load speed
- Helps Googlebot crawl efficiently
Google explicitly supports 304 responses and uses them to determine whether content needs re-crawling.
When It Can Hurt SEO
- If important pages always return 304 despite content updates
- If caching rules are misconfigured
- If dynamic pages incorrectly serve 304 responses
When Should You Use a 304 Status Code?
Use HTTP 304 for:
- Static assets (JS, CSS, images)
- Blog posts with infrequent updates
- Large websites managing crawl budget
It is especially useful for enterprise and content-heavy websites.
When Can 304 Status Codes Become a Problem?
Avoid overusing 304 responses on:
- News websites
- E-commerce product pages
- Frequently updated landing pages
If content changes but still returns 304, search engines may miss important updates.
How to Check 304 Status Codes
You can identify 304 responses using:
- Chrome DevTools → Network tab
- Google Search Console → Crawl stats
- Server log analysis
These tools help you understand whether 304 responses are intentional or accidental.
304 vs 301 vs 302 vs 303 Status Codes
| Status Code | Purpose |
|---|---|
| 301 | Permanent redirect |
| 302 | Temporary redirect |
| 303 | Redirect after form submission |
| 304 | Cached content validation |
Each serves a very different SEO and technical purpose.
Should You Worry About 304 Status Codes?
No – if implemented correctly.
A 304 status code is a performance optimization tool, not an SEO issue. When aligned with proper caching strategy, it helps both users and search engines.
