Table of Contents

• Q: Browser said: "414 Request-URI Too Large" - So how long are URI allowed
• A 414 Request-URI Too Large error means the server refused your request because the URL exceeded what it is willing (or configured) to accept.
  • Typical Maximum URL Lengths
• Browsers
• Servers
  • Nginx
  • Apache
  • IIS (Windows Server)
• Reverse Proxies / CDNs
  • 3 Summary
    • 👉 8 KB (common defaults)
    • 👉 16–32 KB (when configured larger)
  • 3 Fixes
    • ✔ Use POST instead of GET** for large data
    • ✔ Remove unnecessary query parameters
    • ✔ Compress or shorten the data (e.g., base64 → gzip)
    • ✔ URL-shortening logic for huge client parameters
  • 3 Default Nginx Limits (Ubuntu 20.04 / 22.04 packages)
    • 1. Maximum request line size
    • 2. Maximum header size
    • 👉 Your URL cannot exceed ~8 KB
  • 3 How to Increase URL Size Limit (Nginx)
  • 3 Absolute Limit
  • 3 Quick Rule of Thumb
    • Nginx on Ubuntu 1.18.0 only accepts URLs ≤ 8 KB
    • It will accept up to ~32 KB safely, ~64 KB max.

WEB > URI > Max length #

Q: Browser said: "414 Request-URI Too Large" - So how long are URI allowed #

A 414 Request-URI Too Large error means the server refused your request because the URL exceeded what it is willing (or configured) to accept. #

There is no universal maximum URL length across the internet — it depends on:

• the browser
• the web server (Apache, Nginx, etc.)
• intermediate systems (proxies, load balancers)

Below are the real-world limits.

Typical Maximum URL Lengths #

Browsers #

⚠️ Browsers rarely impose the limiting factor — servers do.

Servers #

Nginx #

• Default allowed request line: 8 KB (large_client_header_buffers 4 8k;)
• Can be increased to: 32 KB – 64 KB safely

Apache #

• Default 8 KB for LimitRequestLine
• Can increase to up to 128 KB

IIS (Windows Server) #

• Default: 16 KB
• Maximum configurable: 16 KB (hard limit)

Reverse Proxies / CDNs #

Often the tightest restrictions.

3 Summary #

Most servers reject URLs that exceed:

👉 8 KB (common defaults) #

or

👉 16–32 KB (when configured larger) #

If you get 414 Request-URI Too Large, it means:

• the URL was too long for that server’s configuration
• often caused by too many query parameters, long base64 strings, or large GET requests

3 Fixes #

To avoid 414 errors:

✔ Use POST instead of GET** for large data #

✔ Remove unnecessary query parameters #

✔ Compress or shorten the data (e.g., base64 → gzip) #

✔ URL-shortening logic for huge client parameters #

Q: #

nginx/1.18.0 (Ubuntu)

For nginx/1.18.0 (Ubuntu), the default limits that cause 414 Request-URI Too Large are:

3 Default Nginx Limits (Ubuntu 20.04 / 22.04 packages) #

1. Maximum request line size #

large_client_header_buffers 4 8k;

Meaning:

• max 8 KB allowed for the request line → this includes the URL (path + query string)

2. Maximum header size #

client_header_buffer_size 1k;
large_client_header_buffers 4 8k;

So effectively:

👉 Your URL cannot exceed ~8 KB #

(about 8192 characters, measured after URL-encoding)

If the URL is longer, Nginx returns:

414 Request-URI Too Large

3 How to Increase URL Size Limit (Nginx) #

Edit /etc/nginx/nginx.conf or a site in /etc/nginx/sites-available/ inside the http {} or server {} block:

client_header_buffer_size 16k;
large_client_header_buffers 4 32k;

Safe values:

• 16k request header buffer
• 32k max request line

Some people go up to 64k, but 32k is common and safe.

Then reload:

sudo nginx -t
sudo systemctl reload nginx

3 Absolute Limit #

At maximum tuning, Nginx can handle:

👉 up to ~64 KB URLs

It cannot go beyond that because of internal limits and diminishing returns.

3 Quick Rule of Thumb #

If you don't reconfigure anything:

Nginx on Ubuntu 1.18.0 only accepts URLs ≤ 8 KB #

If you configure buffers:

It will accept up to ~32 KB safely, ~64 KB max. #

If you want, you can paste the URL (or just its approximate length), and I can tell you exactly whether it will pass after tuning.