Most Common HTTP Status Codes Every SEO Should Know

Last Updated on August 7, 2026 by Rishi

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You migrate a site, launch a redesign, or clean up old URLs — and a week later, traffic quietly drops for no obvious reason. Nine times out of ten, the culprit is sitting in plain sight: a handful of HTTP status codes doing the wrong thing without anyone noticing.

HTTP status codes are one of those technical SEO fundamentals that separate a smooth migration from a ranking disaster. Google’s own crawling infrastructure leans on them constantly — to decide whether a page gets indexed, whether link equity transfers after a redirect, and whether your site looks stable enough to keep crawling at full speed. Get them wrong, and Googlebot quietly loses trust in your site long before you notice anything in your analytics.

This guide covers the full list of HTTP status codes, breaks down the most common HTTP status codes SEOs actually deal with day to day, and shows you exactly how to catch problems before they cost you rankings.

What Is an HTTP Status Code?

An HTTP status code is a three-digit response your server sends every time a browser or crawler requests a page. It’s the server’s way of saying “here’s your content,” “it moved,” or “something went wrong.” Every status code falls into one of five classes, and for SEO purposes, three of them do almost all the heavy lifting:

Class	Meaning	Crawler Takeaway
1xx	Informational	Rarely seen by SEOs; the request is still being processed.
2xx	Success	Page loaded correctly and is eligible for indexing.
3xx	Redirection	Content has moved; equity transfer depends on which 3xx code is used.
4xx	Client error	The requested page can’t be found or accessed — not indexed.
5xx	Server error	The server failed to respond — hurts crawl trust if sustained.

According to Google’s own Search Central documentation, a 2xx response gets passed to Google’s indexing pipeline — but that still doesn’t guarantee the page gets indexed. Status codes decide eligibility, not outcome.

Why HTTP Status Codes Matter for SEO

Status codes affect three things Google cares about directly: whether a page can be indexed at all, whether ranking signals transfer when a URL changes, and how much crawl budget Googlebot is willing to spend on your site. A site that returns clean, predictable status codes gets crawled more efficiently. A site full of broken redirects, unexpected errors, or misused temporary redirects starts to look unreliable — and unreliable sites get crawled less often and trusted less when they do.

The Full List of HTTP Status Codes Every SEO Should Know

2xx: Success Codes

200 (OK) — the page loaded successfully. Every indexable page should return this.
201 / 202 (Created / Accepted) — common on APIs; rarely seen on public pages.
204 (No Content) — the server responded but returned nothing. Search Console can flag this as a soft 404 if it happens on a page meant to display content.

3xx: Redirection Codes

301 (Moved Permanently) — the classic permanent redirect; passes link equity and acts as a strong canonical signal.
302 (Found) — a temporary redirect; Google treats it as a weak canonical signal and keeps the original URL indexed.
307 / 308 — the HTTP/1.1 equivalents of 302 and 301, increasingly used by modern frameworks and CDNs.
304 (Not Modified) — tells the crawler the page hasn’t changed since the last crawl, saving crawl budget.

4xx: Client Error Codes

400 (Bad Request) — the server couldn’t understand the request; usually a technical/server-config issue.
401 / 403 (Unauthorized / Forbidden) — the page exists but access is blocked; Googlebot can’t crawl it.
404 (Not Found) — the most familiar error code. A few are normal; a sudden spike after a migration is a red flag.
410 (Gone) — tells Google the page was removed on purpose, which tends to speed up de-indexing versus a plain 404.
429 (Too Many Requests) — you’re rate-limiting Googlebot itself, which slows down crawling of your whole site.

5xx: Server Error Codes

500 (Internal Server Error) — something broke server-side; sustained 500s can get already-indexed URLs dropped within days.
502 / 504 (Bad Gateway / Gateway Timeout) — usually a hosting or CDN issue between servers.
503 (Service Unavailable) — the correct code for planned maintenance, especially paired with a Retry-After header so Google re-queues the page instead of dropping it.

The Most Important HTTP Status Codes for SEO

Of that full list, a much shorter set accounts for nearly every real SEO issue you’ll actually troubleshoot. If you only memorize one table from this article, make it this one:

Code	Name	Why It Matters for SEO
200	OK	The healthy default. Every indexable page must return this.
301	Moved Permanently	Passes link equity and is treated as a strong signal for canonicalization.
302	Found (Temporary)	Weak canonical signal; equity stays with the original URL.
404	Not Found	Normal in small numbers; a spike after a migration signals a problem.
410	Gone	Tells Google the removal is intentional — typically de-indexed faster than a 404.
500	Internal Server Error	Sustained errors slow crawling and can trigger de-indexing within days.
503	Service Unavailable	Safe for planned maintenance if paired with a Retry-After header.

Common Mistakes SEOs Make with Status Codes

Using a 302 for a permanent move — the old URL stays indexed and the new one never fully inherits its ranking signals.
Custom error pages that return 200 instead of 404 — this is the classic soft 404, and it wastes crawl budget on pages Google shouldn’t be indexing.
Long redirect chains — Google follows up to 10 hops before treating the URL as a redirect error, and each extra hop risks leaking signal.
Taking a site down with a generic error instead of a proper 503 during maintenance — this can get pages de-indexed unnecessarily.
Ignoring a rising 429 count, which quietly throttles how much of your site Googlebot is willing to crawl.

How to Check HTTP Status Codes on Your Website

You don’t need to guess. A few reliable ways to check status codes: the URL Inspection tool in Google Search Console, browser developer tools (Network tab), the HTTP status code checker for a quick one-off lookup without opening dev tools, and command-line tools like curl -I for developers who want raw header output. For anything beyond a single URL — like auditing every redirect after a migration — a bulk crawler such as Screaming Frog is worth pairing with a lightweight status code checker for spot-checking technical issues along the way.

Why You Should Regularly Check the HTTP Status Codes of Your Website

Most sites only think about status codes after something breaks — a migration tanks traffic, or a client asks why pages disappeared from Google. Checking status codes proactively, instead of reactively, is what actually protects rankings:

Catch indexing problems early — a page silently returning a 404 or 500 can sit broken for weeks before anyone notices in analytics.
Protect crawl budget — redirect chains, soft 404s, and repeated errors waste the limited time Googlebot spends on your site.
Preserve link equity during migrations — verifying every old URL 301s correctly is the difference between keeping your rankings and starting over.
Spot rate-limiting issues — a rising count of 429 or 503 responses can quietly throttle how much of your site gets crawled.
Confirm redirects actually work as intended — a redirect that returns the wrong code, or chains through multiple hops, can leak ranking signal without any obvious symptoms.

A quick status code check after every deploy, redesign, or content cleanup catches these issues while they’re still a five-minute fix — not a multi-week recovery.

The Future of HTTP Status Codes in SEO

As AI crawlers and answer engines join Googlebot in requesting pages, clean status code behavior matters even more — a crawler that hits repeated errors or messy redirect chains is just as likely to give up on a page whether it’s indexing for traditional search or pulling a passage for an AI answer. Treating status codes as a foundational health check, not a one-time migration task, is quickly becoming table stakes rather than a nice-to-have.

Related Article: SEO Strategy for LLMs

Final Thoughts

HTTP status codes aren’t just a developer concern — they’re one of the clearest ways your business site communicates its health to Google, and increasingly, to AI crawlers too. Knowing the difference between a 301 and a 302, catching soft 404s before they eat your crawl budget, and handling maintenance windows with a proper 503 are small habits that prevent large, hard-to-diagnose ranking problems. Build a quick status code check into every migration, redesign, and content cleanup, and you’ll catch the issues that quietly cost other sites their rankings.

Frequently Asked Questions:

What is an HTTP status code?

It’s a three-digit code a server sends in response to a browser or crawler request, indicating whether the request succeeded, redirected, or failed.

What are the most common HTTP status codes in SEO?

200, 301, 302, 404, 410, 500, and 503 come up most often in day-to-day technical SEO work.

Does a 302 redirect hurt SEO?

Not inherently, but using one for a permanent move means ranking signals don’t fully transfer to the new URL the way they would with a 301.

What’s the difference between a 404 and a 410?

Both mean the page is missing, but a 410 explicitly signals the removal was intentional, which tends to get the URL de-indexed faster.

Do 404 errors hurt my rankings?

A small, normal number of 404s won’t hurt you. A sudden spike, especially after a site change, signals a bigger structural problem worth investigating.

What status code should I use during site maintenance?

503 (Service Unavailable), ideally paired with a Retry-After header, so Google understands the downtime is temporary.

How do I check what status code a page is returning?

Use Google Search Console’s URL Inspection tool, browser dev tools, or a dedicated status code checker for a quick lookup.

Rishi

Rishi Pundir is an entrepreneur and author who enjoys exploring the latest business and technology trends, news, and insights across the web. He graduated in computer science and has years of experience in digital marketing. He is also passionate about writing in-depth articles on business, emerging technologies, innovations, digital marketing, and strategies for online business growth. He is the main editor of Trending Business Tips.