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4xx Client Error
What it means
The URI requested by the client is longer than the server is willing to interpret.
| Property | Detail |
|---|---|
| Status class | 4xx Client Error |
| Defined in | RFC 9110, Section 15.5.15 |
| Cacheable by default | Yes. RFC 9110 lists it as heuristically cacheable, so a cache may reuse it without explicit freshness headers unless Cache-Control says otherwise. |
| Who needs to act | The client, or the developer who built the URL. |
What does HTTP 414 URI Too Long mean?
HTTP 414 URI Too Long means the requested URL is longer than the server is willing to interpret. It usually comes from putting large amounts of data in a query string, such as a long list of IDs, or from a redirect loop that keeps adding to the URL. Moving the data into a POST body fixes it.
How 414 URI Too Long works
HTTP sets no fixed maximum URL length, but RFC 9110 recommends that senders and recipients support at least 8,000 octets, and real servers impose their own caps. nginx, for example, reads the request line into one of its large_client_header_buffers, 8 KB by default, and returns 414 when it does not fit. RFC 9110 names three typical causes: a client that turned a POST into a GET with long query data, a redirect loop in which each hop lengthens the URI, and an attack probing for security holes. Unusually for an error, 414 is heuristically cacheable.
Example 414 request and response
GET /search?ids=10001,10002,10003,...,19999 HTTP/1.1
Host: api.example.com
HTTP/1.1 414 URI Too Long
Content-Type: text/htmlThousands of IDs in the query string push the request line past the server limit before any routing happens.
What causes a 414 URI Too Long
- GET requests that serialise a large filter, search or list of IDs into the query string.
- Redirect loops that append the current URL, or a return-URL parameter, on every hop.
- Tracking or state parameters accumulating each time a link is regenerated.
- Data URIs or base64 content pasted into a link.
How to fix a 414 URI Too Long
If you build the request
- Send large inputs in a POST body instead of the query string.
- Check for a redirect loop: watch the Network tab for a URL that grows on every hop.
- Shorten tracking and state parameters, or keep the state on the server and pass a short key.
If you run the server
- Raise the request-line limit only if long URLs are legitimate; otherwise the limit is a useful protection.
- Fix login or language redirects that embed the current URL in a parameter without guarding against loops.
Related status codes
- 413 Payload Too Large: The request body is too large, not the URL.
- 431 Request Header Fields Too Large: Headers such as cookies exceed the limit.
- 400 Bad Request: Some servers answer a malformed URL with a generic 400.
Tools that help
- URL Decoder makes a long encoded query string readable so you can see what is repeating.
Frequently asked questions
The URI requested by the client is longer than the server is willing to interpret.
Usually caused by passing too much data in a GET request's query string instead of a POST body, or by a redirect loop that keeps lengthening the URL.
Shorten the URL, or switch to a POST request with the data in the body instead of the query string.
The HTTP standard sets no limit. RFC 9110 recommends supporting at least 8,000 octets, and servers, browsers and CDNs each impose their own caps, so keep URLs well under a few thousand characters if they must work everywhere.
Sources
Other 4xx Client Error codes
Reviewed by Raja Jahangir · Last reviewed: October 7, 2026