How long can a URL be?

HTTP sets no limit, but implementations do — commonly around 8 KB at servers and proxies. Keeping URLs under 2,000 characters is the long-standing safe choice.

Why did my redirect produce 414?

A redirect loop that appends a parameter on every hop grows the URL until something refuses it.

HTTP 414 URI Too Long

The request URI is longer than the server is willing to interpret, usually because too much data went into the query string.

Defined in RFC 9110 §15.5.15 — 414 URI Too Long · MDN reference

Where you meet HTTP 414 in production

Search and filter endpoints that put long lists of IDs in the query, GET requests that should have been POSTs, redirect loops that append to the URL each time, and SSO flows carrying large tokens.

Why you would test it

Generate a query string with thousands of IDs and see where your stack breaks. The limit is rarely the server's alone: proxies, CDNs and browsers each have one.

What your client should do about a 414

Move the data into a request body — a POST to a search endpoint is the conventional answer. Do not split the request blindly; filters often have to apply together.

414 versus the codes it gets confused with

414 vs 431 Request Header Fields Too Large — 431 is the headers being too large, including oversized cookies. 414 is the URL itself.
414 vs 413 Content Too Large — 413 is the body. Moving data from the URL to the body can trade a 414 for a 413 if both are too large.

Endpoints that return 414

1 endpoint in this playground answers with 414. Every one is free, needs no signup, and can be called from the browser or with curl.

GET https://funapi.dev/api/faults/v1/status/{code} — Return any status code on demand (200–599) (Fault Injection API) Open & run this endpoint

Questions about HTTP 414

How long can a URL be?: HTTP sets no limit, but implementations do — commonly around 8 KB at servers and proxies. Keeping URLs under 2,000 characters is the long-standing safe choice.
Why did my redirect produce 414?: A redirect loop that appends a parameter on every hop grows the URL until something refuses it.

Other client error codes

All HTTP status codes · All 39 mock REST APIs · Getting started guide

Last updated 15 October 2026