Deprecated: strlen(): Passing null to parameter #1 ($string) of type string is deprecated
PHP 8.1+ warns when null is passed to a built-in function that expects a string/int.
Exact message you may see
Passing null to parameteris deprecated
Seen on:
PHP
Meaning
Internal functions used to coerce null silently. PHP 8.1 deprecates it (and a future version will throw). The value is usually an optional input or missing database field.
Common causes
- Optional request field passed directly to string functions
- Nullable DB column
- Return value of a function that can be null
⚡ Quick fix
- Coalesce:
strlen($name ?? '') - Validate inputs early
- Fix the source of the null
Detailed fix by platform
PHP
- Search logs for "Passing null to parameter" to find every call site after upgrading
How to diagnose
- Function — Which function and parameter?
- Value — Why is it null?
🔧 Still not fixed?
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Most viewed in PHP
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Where this error sits
Origin: Application & API. Errors that are often confused with or caused by this one (click to open):
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Last updated 12 Oct 2026