When you need multi-line strings, heredoc and nowdoc provide a clean alternative to concatenation or escaped quotes.
<<<EOT) behaves like a double-quoted string — variables are interpolated.<<<'EOT') behaves like a single-quoted string — no interpolation, content is literal.Since PHP 7.3 the closing marker no longer needs to be at column 0, so heredoc/nowdoc can be indented naturally inside functions and classes.
<?php
$product = 'Widget';
$price = 9.99;
// Heredoc — variables ARE interpolated
$html = <<<EOT
<div class="product">
<h2>$product</h2>
<p>Price: \$$price</p>
</div>
EOT;
echo $html;
// Nowdoc — NO interpolation (ideal for code snippets or SQL)
$sql = <<<'SQL'
SELECT *
FROM products
WHERE price < $price
SQL;
echo $sql;
// Output contains literal "$price", not 9.99
// Useful for embedding HTML in mailers, templates, etc.
function emailBody(string $name): string
{
return <<<EOT
Hello, $name!
Welcome to our platform.
EOT;
}
Tip: Prefer nowdoc for SQL, regular expressions, or any content that must not undergo variable interpolation — it eliminates a whole class of accidental substitution bugs.