Is PHP compiled or interpreted?

PHP uses a hybrid approach − it is both compiled and interpreted. PHP code is first compiled to intermediate bytecode, which is then interpreted by the Zend Engine at runtime.

How PHP Execution Works

When you run a PHP script, the following process occurs ?

PHP Compiler Responsibilities

The PHP compiler performs several key tasks ?

• Convert PHP source code to bytecode (opcodes) that can be executed by the runtime engine
• Resolve function names, class names, and variable references
• Create a symbol table for efficient variable lookup
• Perform syntax checking and basic optimizations

PHP Interpreter (Zend Engine) Functions

The Zend Engine interpreter handles the execution phase ?

• Processes bytecode instructions line by line
• Manages memory allocation and garbage collection
• Handles runtime exceptions and errors
• Executes built−in and user−defined functions

Example of Bytecode Generation

You can view the generated bytecode using the Zend OPcache extension ?

<?php
function add($a, $b) {
    return $a + $b;
}

$result = add(5, 3);
echo $result;
?>

8

Comparison with Other Languages

Conclusion

PHP is technically both compiled and interpreted. It compiles source code to bytecode at runtime, then interprets that bytecode through the Zend Engine. This hybrid approach provides a balance between development flexibility and execution efficiency.