Seeder v1.4.2

Find, show, share and admire Minecraft seeds (Java edition mostly, Bedrock only if you are interested in biomes).

Works up to 26.3!

!Seeder demo gif

This is a webapp based upon a library (cubiomes) written by cubitect in C and compiled in webassembly by me. Go and give him love. Since the original library is no longer maintained, this app now builds against the actively maintained xpple/cubiomes fork.

It's a React app that uses a WASM build of cubiomes to run the code in your browser, so that you can look up your seeds/find your perfect ones without installing or configuring anything.

Works with every Java version from Beta 1.7 to 26.3. From 1.18 a seed gives the same terrain and biomes on Bedrock too, so the biome map works for Bedrock worlds; structures, strongholds and slime chunks are placed differently there, so those only hold for Java.

Features

Home page

• [x] Open any seed (a number or text, like the game does) or a random one
• [x] Continue with the last seed you opened, or one of your saved worlds
• [x] Old share links still work, they open the new seed page

Seed map

• [x] Generates biomes for a given seed, in the Overworld, the Nether and the End
• [x] Biomes at any height from 1.18
• [x] Terrain shading from 1.18: the map shows hills, mountains and the sea floor
• [x] Find the spawn point, the strongholds and the structures; point at (or tap) an icon to see what it is
• [x] Slime-chunk and chunk-grid overlays
• [x] Move the map using your mouse (drag to pan, mouse wheel to zoom) or your fingers (pinch to zoom)
• [x] Works on phones: full screen map, and everything else in a sheet you pull up
• [x] A dashboard next to the map, in tabs:

Seed finder

• [x] Find seeds with several biomes and several structures at once, many results per search
• [x] Find seeds where you spawn on a small island, with ocean all around
• [x] Presets for common searches (speedrun, island, scenic, structure hunts)
• [x] Every result has a little map you can open, the spawn and where the structures are
• [x] Share a search or its seeds with a link, find more, export results as CSV or JSON, or share a picture of a seed
• [x] Finding rare seeds may slow down your PC while the search is running (seed finding is a very CPU intensive job)

Tools

• [x] Nether portal calculator: Overworld to Nether coordinates, and back
• [x] Stronghold finder: two eyes of ender, no seed needed
• [x] Slime chunk finder: every slime chunk of your seed on a grid, and the best AFK spots
• [x] Circle and sphere generator: circles, ellipses, spheres and domes, layer by layer, with block counts

Ideas

• [ ] Ores and caves
• [ ] Chest loot

Credits

• World generation: cubiomes by Cubitect (MIT licence), via the

• The pixel font is Minecraftia by Andrew Tyler, licensed CC BY-SA 3.0.
• The circle generator's circles follow donatj's Circle Generator (MIT licence),

Not an official Minecraft product. Not approved by or associated with Mojang or Microsoft.

Development

cd seeder
npm install
npm run dev          # http://localhost:3000
npm run build        # static site in seeder/build/
npm test             # unit + component + engine tests (Vitest)
npm run test:e2e     # browser tests against a production build (Playwright)
npm run shots        # the home page pictures (needs cwebp)
npm run og-card      # the social preview picture, from the map one

The Minecraft world generation runs as WebAssembly inside Web Workers; the compiled engine is committed under seeder/public/workers/, so no C toolchain is needed to work on the app. The engine tests load that same WASM headlessly in Node.

Licence

MIT, see LICENSE.