Minecraft Datapack Seed Map
Worldgen datapacks like Terralith and Tectonic rewrite the biomes your seed generates, which means every ordinary seed map is wrong the moment you install one. Drop the datapack ZIP onto this map and it reads the pack’s own noise settings and biome definitions, then regenerates the map from them — so what you see is the world that pack will actually build for your seed. It runs entirely in your browser: the ZIP is never uploaded anywhere. Any pack that ships standard Minecraft worldgen JSON works, for the Overworld, the Nether and the End.
How to use it
- Open ezseed.net, choose Java Edition and enter your world seed.
- Click the Datapack button next to the seed to open the datapack panel.
- Pick a pack from Modrinth (the build for your version is selected for you), or drop the datapack ZIP anywhere on the map.
- Wait for the map to regenerate — the biome colours change to the pack’s own biomes.
- Pan and zoom as usual. Hover a spot to read the pack’s biome there, and share the link: a Modrinth pack travels with it.
Good to know
A worldgen datapack replaces the noise settings and biome list the game uses to build a world. That is why a vanilla seed map and a Terralith world made from the same seed look nothing alike — the seed is the same, the generator is not. This map reads the pack you give it rather than guessing: it parses the worldgen JSON out of the ZIP, registers the pack’s noise parameters, and regenerates every tile through them.
Biomes are computed the way the game computes them, and were checked against the real game with Terralith, Tectonic, Continents, Lithosphere, Incendium and Nullscape on Java 1.20 to 26.2. Java 26.3 changed the worldgen format and is not supported yet. A pack that needs mod code or a worldgen type outside the vanilla format is refused with a message naming what is missing, rather than drawn wrong. Structures that depend on biomes are hidden while a pack is on, and the 3D viewer still shows vanilla terrain.
Nothing leaves your machine. The ZIP is read in the browser and the generation runs on your own CPU, which is also why a large pack takes a moment to apply the first time.
FAQ
Which datapacks are supported?
Any pack that ships standard Minecraft worldgen JSON — noise settings, biome definitions and biome sources — for Java 1.20 to 26.2. The map was checked against the real game with Terralith, Tectonic, Continents, Lithosphere, Incendium, Nullscape and Amplified Nether, and it applies the overlays a pack ships for your version. Packs that change only structures, loot or recipes load without changing the map, because they do not change world generation.
Do I have to upload my datapack anywhere?
No. The ZIP is read in your browser and never sent to a server. The whole generator runs locally in your browser, which is the same reason the map works with no account and no download.
Why does my Terralith world look different from the map?
Check that the Minecraft version selected on the map matches the version the pack targets, and that you are on Java Edition — datapack worldgen is Java only. A version mismatch is the usual cause: the same pack on a different generator version produces different terrain.
Do structure markers work with a datapack?
Structures whose placement depends on biomes are hidden while a pack is on, because the pack changes where they can go. The markers that stay use the vanilla placement rules, and a pack can still move, remove or add structure sets in ways those rules do not describe.