Download websites that use OpenSwoole

About OpenSwoole

Fingerprinting a runtime is only possible when the runtime is the thing answering the request, and that is exactly the position OpenSwoole puts itself in. Instead of running as a script a web server invokes and then forgets, it keeps a PHP process alive and lets that process hold connections open, which is why the Web frameworks label fits it better than a library label would. Released under Apache 2.0 and dated in our records to 2021, the project exists because the request per process model cannot hold a websocket open or serve many concurrent clients from one host.

The engineering reason a team reaches for it explains who ends up in the list. A PHP application that needs to push updates rather than answer and exit has a few options. Rewrite the service in another language, bolt a second runtime onto the stack, or make the PHP process itself long lived. Choosing the last one keeps a single language and a single codebase, which appeals to teams with deep PHP expertise and no appetite for operating a second runtime. Chat, live dashboards, game backends, notification services and internal APIs are the usual results.

Counting any of that from outside is another matter. As of October 2026 we record 5 sites, and the number describes a small visible corner of real usage. A production deployment usually sits behind a reverse proxy that answers the public request and rewrites the server header, so the engine disappears from external view entirely. What stays detectable are deployments where the process faces the internet directly, or where headers pass through untouched, which skews the list towards smaller setups, internal tools published on a hostname, and teams who never changed a default.

A skew that predictable is still workable once you know it is there. Every domain in the set is a confirmed live PHP service running an asynchronous engine, which is a narrow and self selecting technical group. Vendors selling observability, managed hosting or runtime support to PHP teams want that group specifically. So do researchers asking whether the language is retaining workloads that would otherwise have migrated elsewhere.

An open source project has no billing system to count from, which is why an external scan is the only census available for software like this. Checking one domain answers whether that host is running the engine right now. The export answers where the engine is deployed at all, what sits in front of it, which country domains it clusters on, and whether the population grows or shrinks between releases. Those are the questions the project's own maintainers, and anybody selling to its users, have no other way of answering.