Easy Slice Portal

To light a strip, the player places an obsidian base on the spot where the portal should go, adds obsidian caps at both ends of that row, and then crouches and strikes the top face of the obsidian with Flint Steel. The mod detects the correct orientation on its own, so strips can run along either the X or the Z axis, and the whole 1×N portal is created in one click.

The mod only places and keeps one-block-high portal blocks, and it leaves normal rectangular portals untouched, so those behave exactly like vanilla. A lightweight mixin stops the low portal blocks from popping out because of neighbor updates. Stepping into one of these portals runs the identical logic that a standard Nether portal uses, and connections are resolved by vanilla rules, so the game links to whichever existing portal is closest.

The mod adds no custom blocks, entities, commands or dimensions. It runs on the server, and the environment is client and server, so the server and every player are expected to have it. Clients connecting to a server that runs it are recommended to install it too, so that sounds and particles match. Easy Slice Portal is for Fabric, with files for 1.21 and 1.21.1, and the latest build is 1.0.1 for 1.21.1.