$string = "This is a {string} with {words} wrapped in {curly} brackets.";
// Define the regex pattern
$pattern = '/\{(.*?)\}/';
// Use preg_match_all to find all matches
preg_match_all($pattern, $string, $matches);
print_r($matches[1]);
/*
run:
Array
(
[0] => string
[1] => words
[2] => curly
)
*/