# PSRs ***

After years, PHP-FIG has been established as the group witch takes care about the PSR Standard. PSR stands for PHP Standard Recommendation. Since they started with PSR-0 a lot in the PHP ecosystem improved in our opinion! So, with our PSRs we don’t want to replace PHP-FIG neither getting in conflict with them. appserver.io is not a framework per definition, but a infrastructure solution and a new player in the PHP ecosystem that provides functionality witch has NOT been available so far or was partially been covered by webservers like nginx or Apache.

Intention behind our own PSRs


The intention behind our PSRs is, to provide Admins, DevOps, Solution Providers, Developers and all other contributors of appserver.io with a public, stable and easily accessible API witch makes it possible to implement own applications and components.

With version 1.0.0 we will provide sequenced application specific PSRs

Application specific PSRs

Application specific PSRs describe all interfaces a developer needs to build an application that runs on appserver.io and uses Server-Side component types like Servlets, Session or Message Driven beans.

With the final version 1.0.0 Iron Horse, we guarantee, that these PSRs will follow Semantic Versioning and take care of backward compatibility for these application specific PSRs. Compatibility will never be broken within a major version.

Server specific PSRs

Besides application specific PSRs we are also working on PSRs witch are implemented by containers, servers or modules appserver.io is built on.

As long as these PSRs are in progress, there will be no guarantee for their compatibility. We hope we can extend the guarantee with the next releases, so it will also include the server specific PSRs within tight semantic versioning.

What does our PSRs mean for you


In case you implement an application that works with 1.0.0, we guarantee that it will run without structural changes on all releases < 2.0.0. The application specific PSRs will only be supplemented with new interfaces and classes to extend the feature set. Existing interfaces and their methods will not be changed.

Our vision regarding PSRs


As our PSRs cover a higher level then the PSRs maintained by PHP-FIG we hope someday we will have the possibility to merge them together and let them be maintained and extended by the PHP community. The appserver.io is the only infrastructure (to the best of our knowledge) for PHP, completely written in PHP including the PSRs. The PSRs will hopefully help other developers and companies to get a better understanding of how certain mechanisms are implemented and encourage People to work on their autonomous, compatible solutions, which will enable developers to deploy their applications on every PHP Application Server that implements these PSRs.

Soon, you will find detailed information for each PSR on our appserver-io-psr organisation page on GitHub.