HTTP 509 Bandwidth Limit Exceeded
HTTP 509 Bandwidth Limit Exceeded is an unofficial, non-standard status code used by some shared hosting providers to indicate that a website has exceeded its monthly bandwidth quota. It is not defined in any IANA-assigned RFC and has no standardized behavior — different hosting providers may implement it differently or use other codes for the same condition.
Quick reference
| Code | 509 |
|---|---|
| Name | Bandwidth Limit Exceeded |
| Category | 5xx Server Errors |
| Specification | IANA Registry (Unassigned) |
| IANA status | Unassigned — unofficial extension code |
| Cacheable | No |
| Client action | Contact the hosting provider. Bandwidth quota must be increased or the next billing period must begin. |
| In-depth guide | HTTP 509 full guide → |
What HTTP 509 means
509 is not an official HTTP status code. IANA has not assigned it — it appears as "Unassigned" in the HTTP status code registry. It was informally adopted by cPanel-based shared hosting providers (including Apache with certain modules) to signal that the hosted website has consumed its allocated monthly bandwidth and is temporarily suspended.
When a site returns 509, visitors see an error page rather than the site content. The site is typically restored automatically at the start of the next billing cycle, or when the account holder upgrades their bandwidth plan. The 509 code is generated by the hosting provider's infrastructure, not by the site's application code.
Because 509 is unofficial, client behavior is undefined by the HTTP specification. Browsers and HTTP clients treat it like any unrecognized 5xx code — typically displaying it as a server error. It is not cached and should not be retried automatically.
Common causes
Shared hosting bandwidth quota exceeded
Shared hosting plans often include a monthly bandwidth cap — total bytes transferred between the server and all visitors. When the site's content delivery exceeds this cap within a billing period, the hosting provider suspends the site and returns 509 for all requests.
Traffic spike from viral content
A blog post, image, or resource that unexpectedly goes viral can consume the entire monthly bandwidth quota in hours. Shared hosting plans with low bandwidth limits are particularly vulnerable.
Hotlinking of assets
Other sites embedding images or files directly from your server (hotlinking) consume your bandwidth without any of the associated traffic to your pages. This can exhaust bandwidth quotas rapidly.
Automated crawling or scraping
Bots that aggressively crawl a site can consume large amounts of bandwidth. A misconfigured or malicious bot that repeatedly downloads the same large files will accelerate quota exhaustion.
How to resolve a 509
- Contact the hosting provider. Upgrade the bandwidth plan, purchase additional bandwidth, or wait for the next billing cycle to begin.
- Check bandwidth usage analytics. Most hosting control panels show which pages or files consumed the most bandwidth. Identify the source of high consumption.
- Block hotlinking. Configure the web server to reject requests for images and assets where the Referer header is from a different domain. Apache's
mod_rewriteand nginx can both block hotlinking. - Add a CDN. Serving static assets through a CDN offloads bandwidth from the origin hosting account and typically does not count against the hosting bandwidth quota.
- Optimize large assets. Compress images, use modern formats (WebP, AVIF), and minify CSS and JavaScript to reduce bytes per request.
509 vs standard bandwidth-related codes
FAQ
What does HTTP 509 Bandwidth Limit Exceeded mean?
HTTP 509 is an unofficial code indicating that the website has exceeded its monthly bandwidth quota on a shared hosting plan. The site is suspended until the quota resets or is increased. Contact the hosting provider to resolve it.
Is 509 an official HTTP status code?
No. IANA lists 509 as unassigned — it is not part of the official HTTP specification. It is a non-standard extension used by some hosting providers, primarily those using cPanel-based infrastructure.
How long does a 509 last?
Until the hosting account's bandwidth quota is reset (typically at the monthly billing date) or until the account holder upgrades the plan or purchases additional bandwidth. The hosting provider's control panel will show when the quota resets.
Can clients distinguish 509 from 500?
Without knowing the hosting provider's specific implementation, clients cannot distinguish 509 from other unrecognized 5xx codes. The response body may contain a hosting-provider-specific error page explaining the bandwidth suspension.
Related resources
On this site: HTTP 509 Bandwidth Limit Exceeded — full guide · HTTP 429 Too Many Requests · HTTP 503 Service Unavailable · All 5xx server errors
Standards: IANA HTTP Status Code Registry · MDN Web Docs: HTTP Status