Crafty Seed Map vs SeedLander

Crafty Seed Map is a free web tool for Minecraft Java players who want to inspect seed terrain and locate biomes, slime chunks, and structures. It accepts numeric seeds and text seeds, hashing text as the game does, and can display the Overworld, Nether, and End. A nearest-search function works outward from an origin in a spiral and checks structure candidates against biome requirements. Named, colored markers are stored in the browser for each seed, while a shareable URL preserves the seed, viewport, visible layers, and biome highlight. World generation runs locally in the browser, and the seed is not sent to a server. The biome layer uses a WebAssembly port of cubiomes, and structure locations are revalidated against biomes. Supported versions are Java Edition 1.18.2, 1.19.4, 1.20.6, 1.21.1, and 1.21.3; Bedrock Edition is not supported. The map is described as mobile-first and includes pinch-to-zoom controls, with no ads. Buried treasure, mineshafts, geodes, desert wells, and end gateways appear only at sufficiently close zoom levels.

SeedLander is a browser-based toolkit for analysing Minecraft seeds in Java Edition and Bedrock Edition, including Java Large Biomes. Its tools cover biome maps, structure searches, ore predictions, slime chunk calculations, portal management, and team collaboration. The structure finder covers 25+ types and provides coordinates for places such as villages, strongholds, temples, mansions, and monuments. SeedLander states that most structure results on Java and Bedrock are 97%+ accurate, while cautioning that they are predictions rather than guarantees. The tools run in the browser using WebAssembly, and seeds are not sent to SeedLander servers for processing. Map, finder, and account pages support touch use on phones and tablets; a dedicated mobile app is on the roadmap. The free Basic plan includes all seed tools, 10 custom markers, and three saved portal pairs. Premium costs £1.99 per month per world and adds unlimited markers and portals, ore tracking, structure completion tracking, notes, and an activity log. A Team add-on costs £2.99 per month per world on top of Premium.