What are the differences in die() and exit() in PHP?

In PHP, die() and exit() are functionally identical language constructs that terminate script execution. However, there are some subtle differences worth understanding.

Official Documentation

The PHP Manual confirms their equivalence ?

For exit() ?

"This language construct is equivalent to die()."

For die() ?

"This language construct is equivalent to exit()."

Functional Comparison

Both functions work identically and can accept an optional parameter ?

<?php
    // Both stop execution immediately
    echo "Before exit
";
    exit("Script terminated with exit()");
    echo "This will never execute";
?>

Before exit
Script terminated with exit()

<?php
    // Same behavior with die()
    echo "Before die
";
    die("Script terminated with die()");
    echo "This will never execute";
?>

Before die
Script terminated with die()

Key Differences

Usage Examples

Using exit() for Normal Termination

<?php
    $config_loaded = true;
    
    if ($config_loaded) {
        echo "Configuration loaded successfully
";
        exit(0); // Success exit code
    }
?>

Configuration loaded successfully

Using die() for Error Conditions

<?php
    $database_connected = false;
    
    if (!$database_connected) {
        die("ERROR: Unable to connect to database!");
    }
    
    echo "This won't execute";
?>

ERROR: Unable to connect to database!

Conclusion

die() and exit() are functionally identical in PHP, with only minimal parsing time differences. By convention, use exit() for normal termination and die() for error conditions to improve code readability.