What is the difference between the == (Equal) and === (Identical) comparison operators in PHP 8+?

Short answer

== compares values after attempting type conversion, while === compares both value and type without implicit conversion.

Explanation

In PHP versions before PHP 8, implicit comparisons with == caused security problems (for example, 0 == 'admin' returned true). PHP 8 made comparisons between numbers and strings more careful, but the standard interview advice is still to use === everywhere to avoid surprises from implicit conversions.

Code example

0 === "0"; // false
0 == "0";  // true
false === 0; // false

Common mistakes

• Using == to compare passwords or security tokens, allowing guessing vulnerabilities and Type Juggling.

Follow-up questions

• What is the difference between Type Juggling and declare(strict_types=1) in PHP?
• What is the difference between the Null Coalescing operator (??) and the Nullsafe Operator (?->) in modern PHP?

Sources

• PHP docs — Comparison Operators