Editing Portal:SaaS and Web Development (section)

=== PAGI and asynchronous Perl web applications ===

A newer development is '''PAGI''', the '''Perl Asynchronous Gateway Interface'''. MetaCPAN describes PAGI as a specification for asynchronous Perl web applications and as a spiritual successor to PSGI. It defines a standard interface between async-capable Perl web servers, frameworks, and applications, supporting HTTP/1.1, WebSockets, and Server-Sent Events.<ref>MetaCPAN, “PAGI - Perl Asynchronous Gateway Interface,” https://metacpan.org/pod/PAGI, accessed July 3, 2026.</ref>

PAGI is best understood as a response to changes in web architecture. PSGI was designed around the request/response model that dominated traditional web applications. Modern applications often need long-lived connections, streaming responses, WebSockets, async backends, real-time updates, and event-driven services.

PAGI aims to bring Perl into that async web world in a more standardized way. It is still newer and less historically proven than PSGI, but its appearance is significant. It shows that Perl web developers continue to think about how Perl should interact with modern web protocols and async application patterns.

PAGI also reflects a broader trend across programming languages. Python developed ASGI as an async successor to WSGI. Perl’s PAGI is similar in spirit: a gateway interface intended for asynchronous web applications rather than only classic synchronous request/response applications.