CGI · PSGI
Insights
CGI vs PSGI: which fits an existing Perl application?
Compare CGI and PSGI for existing Perl web applications, including process model, deployment, middleware, hosting constraints and migration decisions.
Maple · Mecha · Perl
01
CGI keeps the process model simple
Each request starts a process, the web server provides the environment and process exit naturally cleans up state. This can be operationally simple in low-volume or constrained hosting environments.
02
PSGI standardizes a persistent application interface
A PSGI application can run behind multiple servers, use middleware and avoid paying full process startup for each request. That opens useful deployment and composition options.
03
Deployment constraints matter
If the hosting environment only supports CGI, a theoretical PSGI advantage may not be useful. If persistent workers and middleware are already available, PSGI may reduce friction.
04
Migration can be incremental
Move business logic into modules first. A thin request boundary makes it possible to support CGI today and another interface later without rewriting the domain code.
05
Choose based on outcomes
The decision should be tied to performance, hosting, observability, middleware, deployment or maintainability goals—not the age of the acronym.
06
A practical next step
Write down what CGI is preventing you from doing. If the answer is concrete, evaluate PSGI against that list. If not, improve the current boundary first.
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