max_input_vars 🐘 PHP

Warning: Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini.

The form submitted more fields than PHP’s max_input_vars allows; extra fields were silently dropped.

Seen on: PHP

Meaning

Large admin forms (WordPress menus, WooCommerce variations, settings pages) can exceed the default 1000 inputs. PHP truncates the data, so saves look successful but lose items.

Common causes

  • Very large forms (menus with many items, bulk edits)
  • Default max_input_vars = 1000

⚡ Quick fix

  1. Raise max_input_vars = 5000
  2. Split huge forms
  3. Submit large data as JSON instead of many fields

Detailed fix by platform

WordPress

  1. Menus losing items on save is the classic symptom — raise max_input_vars

How to diagnose

  1. Count — How many fields does the form post?
  2. Limit — ini_get('max_input_vars')

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