Run PHP 8 online

What's in PHP 8

• JIT enabled; typed properties, enums, readonly, constructor promotion all stable.
• Fibers and PSR-standard stream primitives are on tap for algorithmic workloads.
• Backwards-compatible surface — code that runs here also runs on 8.4.

What you get in PHP 8

Clicking "Run now" opens the playground with this exact code and a matching test case — passes on first Run.

<?php $n = (int)trim(fgets(STDIN)); echo ($n * 2) . "\n";

How ls-judge runs PHP 8

Every submission is compiled and executed inside its own Firecracker microVM — the same isolation primitive AWS Lambda uses. No shared container, no shared kernel with other users' code. The PHP 8toolchain shipped with the microVM is the real thing (not a browser-side emulation): syscalls behave the way they do in production, and the compile / runtime behaviour matches what you would see on your own machine with that version installed.

Feed stdin from the Tests panel, watch verdicts stream per test case over a WebSocket. Free to use, no sign-up, works from any browser.