How a crack works
Every generated feature leaks a few bits of the world seed. Explore, let the mod pick up structures automatically, and once enough bits are collected the seed snaps open. On 1.18+ you need 40 bits from liftable structures plus 32 regular bits.
Optional: install ViaFabric to join servers running lower Minecraft versions. Seeds cracked on 10+ player servers can be submitted to the public seed sheet.
Supported features
Minecraft 1.18 and higher
Dungeon and fungus cracking no longer work. In the config GUI disable Emeralds, Gateways, Biomes, Desert wells and Warped fungi — they can feed the cracker wrong data.
Minecraft 1.17 and below
Overworld: run around until the mod finds a dungeon. Nether: search warped fungus in warped forests. End: visit 5+ end cities or gateways, then return to the centre for the pillar seed.