Encounterizer
Build balanced encounters, forecast the battle, and run the whole session — monsters, maps, puzzles, and spells in one free DM toolkit for D&D 5.5e.
Encounter Builder
Build balanced D&D 5.5e encounters with 2024 XP budgets, then run the Battle Forecast — 1,000 simulated fights before your party rolls initiative.
Monster Bestiary
Browse 331 SRD 5.2.1 monsters with deep filters — CR, type, movement, damage types, resistances — or import your own from JSON.
Battle Map Generator
Procedural battle maps for D&D — BSP dungeons, cellular-automata caves, and outdoor terrain, tuned per environment.
Puzzle Generator
Ready-to-run riddles, ciphers, and minigames with DM briefs, read-aloud text, player handouts, and progressive hints.
Non-Combat Challenges
Social encounters, exploration hazards, skill challenges, and traps — complete with stakes, complications, and outcomes.
Spell Reference
Instant spell lookup with mechanics-first summaries, filters for level, school, class, concentration, and side-by-side pinning.
Powered by the Rules
Everything runs in your browser — no accounts, no server, no tracking. Encounters are shareable by link, and your data never leaves your device.