MultiLoader-Template VS architectury-api

The two main ways I know of are "Multiloader-Template style" and "using Architectury-Loom". Archloom is a big Gradle plugin that tries to do everything for you, multiloader-template is less of a software package and more of a code style. I'm not familiar with archloom but i've written a bunch of mods with the multiloader-template style.

This mod wouldn't be possible without Statement Library, which does all the heavy lifting (that said, it is required on both server and client). Also thanks to Jaredlll08 and Darkhax for creating Multiloader Template!

As a developer I want as many players to enjoy my work as possible, that's why I prefer both and have worked on tools to make it easier for developers to release for both.

Regardless of what you choose, If you do want to support both down the line there is a template by Darkhax, jaredlll08 and a few others which makes compiling for both easier by having a common source https://github.com/jaredlll08/MultiLoader-Template

It's the end of the world as we know it.

You can clone https://github.com/jaredlll08/MultiLoader-Template and see how it works, I know that ForgeGradle fixed a bug they had with multiproject configurations, but I'm not sure if any of the other problems are solved.

Architectury, an API for Multiplatform mod support. Needed for Identity.

Using Architectury is likely the easiest method

Okay, with that out of the way, here's what I believe to be true: There is no such thing as a one-size-fits-all code "translator" or "bridge" that can translate regular Fabric code into something that runs on Forge, or vice-versa, and something like this isn't possible in the way I think you're imagining it. Forge and Fabric work very differently from one another under the hood. There is no library that allows you to write Fabric code that works on Forge, and there probably never will be. However, there are some projects out there that aim to lessen the impact of this problem. Architectury is one of these projects. Architectury can translate some parts of a mod between the two loaders, but the mod still has to be built around it. You can't just add it to a Fabric mod and expect it to run on Forge (or vice-versa). Instead, the mod has to be created with it in mind all the way through. Mods can not be converted between Forge<->Fabric automatically. Manual porting is possible, and mods can be built to run on both loaders, but it is not possible to make a universally applicable "converter".

It has been in pre-Alpha for over a year. It won't be happening any time soon, and will behave like Architectury, but with significantly more abstraction for the modder, if / when completed.