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 DATAPACK in the top bar to open the datapack panel.
- Drag the datapack ZIP onto the drop zone, or click it to browse for the file.
- Wait for the map to regenerate — the biome colours change to the pack’s own biomes.
- Pan and zoom as usual, or switch to the 3D viewer to fly over the modified terrain.
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.
The feature is marked experimental for an honest reason. Packs that only add or reshape biomes through standard worldgen JSON preview well. Packs that rely on custom carvers, structure sets or code beyond the vanilla worldgen format will render their biomes but not those extra features, and a pack built for a Minecraft version far from the one you selected can fail to load at all. Structure markers stay on the vanilla placement rules, so treat them as approximate on a heavily modified world.
Nothing leaves your machine. The ZIP is read in the browser and the generation runs in WebAssembly 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 Minecraft 1.20 and later. The parser has been verified against Terralith, Tectonic, Incendium and Nullscape, and it handles Lithostitched-based packs and the multiple pack formats Terralith ships. Packs that change only structures, loot or recipes will 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 WebAssembly, 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?
They still use vanilla placement rules, so treat them as approximate on a heavily modified world. Biomes are regenerated from the pack; structures are not, because a pack can move, remove or add structure sets in ways the vanilla rules do not describe.