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
Verified logic puzzles, riddles, ciphers, and contests — themed, seeded, and shareable, with print-ready player handouts.
Non-Combat Challenges
Skill challenges, social encounters, journeys, complex traps, chases, and investigations — levered, themed, seeded, and shareable.
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.