This page is about the PHP interpreter environment inside the Riza Code Interpreter API. We have not yet published an API client library for PHP.


Riza runs the CGI version of PHP 8.2.6 compiled to WASM. The entire standard library is included.

Because PHP is running in CGI mode (rather than CLI mode) there are a few quirks. For instance there are miscellaneous environment variables set that aren’t meaningful in the context of a standalone script.

We’ve done some work to round off the rough edges, though there are limitations.


When PHP is running as a CGI program it doesn’t provide access to the constants STDIN, STDOUT and STDERR and corresponding php://stdin, php://stdout and php://stderr I/O streams. The php://input and php://output streams work as expected.

The PHP interpreter also doesn’t populate command line parameters in $argv when running as a CGI program.

See our roadmap for planned future improvements.


You can write to stdout with echo or using the php://output stream. Write to stderr with error_log.

echo "Hello, ";
file_put_contents("php://output", "world!");
error_log("Something went wrong");


You can read from stdin using the php://input stream, and access environment variables using $_ENV. Unfortunately $argv isn’t populated.

$input = file_get_contents("php://input");
$foo = $_ENV["FOO"];