PHP 8.1 release notes (via) PHP is gaining “Fibers” for lightweight cooperative concurrency—very similar to Python asyncio. Interestingly you don’t need to use separate syntax like “await fn()” to call them—calls to non-blocking functions are visually indistinguishable from calls to blocking functions. Considering how much additional library complexity has emerged in Python world from having these two different colours of functions it’s noteworthy that PHP has chosen to go in a different direction here.