What data packs do
Data packs tweak Minecraft's mechanics without mods. They can add crafting recipes, change what mobs drop, create custom advancements, modify world generation, and run commands automatically. All in vanilla Minecraft.
They're more limited than mods—you can't add truly new blocks or items, just tweak existing mechanics. But they work on servers without requiring players to install anything, and removing them is as simple as deleting a file.
Installing with GDLauncher (all worlds)
Open your instance and go to the Addons tab. Click Add Addons, then select Data Packs from the dropdown on the left of the search bar. Find a data pack and click Download.
Data packs installed this way apply to all worlds in that instance. If you want different packs for different worlds, use the per-world method below.
Per-world installation
For more control, you can install data packs to specific worlds only. Right-click your instance in GDLauncher, select More options → Open folder. Navigate into the instance folder, then saves/[your world]/datapacks and drop the .zip in there.
Load the world and run /reload in chat. Check if it worked with /datapack list. Green means enabled, red means disabled.
Installing on a new world
When creating a new world in Minecraft, click "Data Packs" before generating. Click "Open Pack Folder" and copy your .zip file in. Go back to Minecraft, hit refresh, move the pack to "Selected", and create your world.
Popular data packs
Vanilla Tweaks is a must-know. It's a website that lets you pick and choose from hundreds of small tweaks: one player sleep, mob heads, custom armor stand poses, and more. You build your own custom pack from a menu.
Beyond that, you'll find packs for craftable items that normally aren't, quality-of-life improvements, and gameplay challenges.
Troubleshooting
Pack not loading? Make sure it's a .zip file (don't extract it) and in the right datapacks folder. Run /reload and check /datapack list.
Shows as incompatible? The pack might be for a different Minecraft version. Sometimes they work anyway despite the warning, but check for an updated version if you have issues.
Features not working? Make sure cheats are enabled (for commands to work) and check if the pack has dependencies on other packs.