What is the maximum URL length?
HTTP sets no fixed limit, but RFC 9110 recommends supporting at least 8000 octets. Browsers, servers, and CDNs each have their own caps, so keep URLs well under that.
HTTP 414 URI TOO LONG
The URL is longer than the server will read. 414 belongs to the 4xx client error class and is defined in RFC 9110.
Loading the workbench.
About HTTP 414
What Does HTTP 414 URI Too Long Mean?
The URL is longer than the server will read. The code is registered with IANA and defined in RFC 9110.
Client error: the request has a problem, so it cannot be fulfilled as sent. Every code from 400 to 499 shares that general meaning, so a client that does not recognise 414 must treat it like 400.
When Do You See a 414 Response?
414 URI Too Long means the request target is longer than the server is willing to parse. It happens when large amounts of data are stuffed into query strings, for example long filter lists, encoded JSON, or a form that uses GET for big input, and with redirect loops that keep appending parameters. Servers often cap request lines at around 8 KB, and some proxies and CDNs use smaller limits.
How Do You Fix a 414?
Clients should move large data into a request body using POST, or store state server-side and pass a short identifier. Check for redirect loops that grow the URL on every hop. Server operators can raise the limit, such as large_client_header_buffers in nginx, but very long URLs also break in logs and browsers, so shortening them is the durable fix. A 414 is cacheable by default.
What Does a 414 Response Look Like?
HTTP/1.1 414 URI Too Long
Content-Type: text/html
Connection: close414 is cacheable by default under RFC 9110: a browser or CDN may store it and reuse it even without explicit freshness headers, using a heuristic lifetime. Send Cache-Control to say exactly how long.
To inspect a real one without sending it anywhere:
- Copy the response headers from your browser Network tab, or from
curl -i. - Paste them into the Header decoder to see every header explained.
- Check caching in the Cache lane.
Which Status Codes Are Related to 414?
- 413 Content Too Large: The body is bigger than the server accepts. Formerly "Payload Too Large".
- 431 Request Header Fields Too Large: One header, or all of them together, are too big. Often oversized cookies.
- 400 Bad Request: The request is malformed: bad syntax, invalid framing, or an unreadable body.
Browse every code on the HTTP status codes page.
What Other Lanes Are in the Reference Section?
- HTTP status codes: Every IANA-registered status code, with a page per code.
- MIME types: File extensions to Content-Type, searchable both ways, plus a Content-Type parser.
- HTTP methods: GET, POST, PUT, PATCH, DELETE and the rest: safe, idempotent, cacheable.
Elsewhere in 2http: Header decoder, Cookie decoder, Cache-Control decoder, CORS checker, User-agent parser, and all eleven lanes on the 2http home page. Part of the 2suite.io privacy-first ecosystem.
Frequently Asked Questions
Can a redirect loop cause 414?
Yes. A redirect that appends a parameter to the URL on each hop makes it grow until a server rejects it as too long.
Is HTTP 414 an error?
Yes. 414 is a client error response: the problem is in the request, so repeating it unchanged will usually fail again.
Is a 414 response cacheable by default?
Yes. RFC 9110 lists 414 as heuristically cacheable, so caches may store it without explicit headers. Use Cache-Control to control how long.
How Can You Verify That Nothing Leaves This Browser?
You do not have to take our word that your headers stay here. Developer tools show every request a page makes, so you can watch this page work and confirm that nothing is sent. The check takes under a minute.
- Open your browser developer tools with
F12, orCmd+Option+Ion a Mac, and select the Network tab. - Reload the page and let it finish. You will see the page's own files, its web fonts, and one anonymous page-view request. Nothing has been typed yet, so none of them can contain your headers.
- Click the clear icon in the Network tab so that the log is empty.
- Paste real headers into any lane and read the result.
- Look at the Network tab again. It is still empty. For extra proof, turn on offline mode after the page loads and every lane keeps working.
Only two things can add a line to that log, and neither carries your headers. Submitting the feedback form sends the vote and comment you typed. Typing characters in a script the page has not displayed yet, such as Cyrillic or Greek, can make the browser fetch the matching font file, and that request names only the font.
2http never sends a request on your behalf: the request builder writes code for you to run, and the meta inspector reads source you paste instead of fetching a URL. The production site also sends a Content-Security-Policy header that tells your browser to refuse connections to anywhere except this site and the anonymous analytics endpoint.