#tabletop

Tabletop dice-probability maths as an API, computed locally and deterministically and exactly — the odds behind the rolls, not the rolls themselves. The advantage endpoint gives the D&D-style chances of beating a target on a d20 (or any die) rolling normally, with advantage (roll twice, keep the higher) or with disadvantage (keep the lower): needing an 11+ is 50 % normally, 75 % with advantage and 25 % with disadvantage, and it reports the average roll — advantage lifts a d20 from 10.5 to about 13.8. The pool endpoint handles success-counting systems (World of Darkness, Shadowrun): for a pool of dice that succeed on a face at or above a threshold it gives the chance per die, the expected number of successes and the exact binomial probability of getting exactly, or at least, a target number — six d10s succeeding on 7+ average 2.4 successes with a 45.6 % chance of three or more. The exploding endpoint gives the mean of an exploding ("acing", open-ended) die that re-rolls and adds on its maximum face — a d6 averages 4.2 instead of 3.5. Everything is computed locally and deterministically, so it is instant and private. Ideal for tabletop, virtual-tabletop, game-design and TTRPG app developers, odds-and-probability helpers, and game-master tools. Pure local computation — no key, no third-party service, instant. Exact maths, no simulation. Live, nothing stored. 3 compute endpoints. For random rolls use a dice-roller API.

api.oanor.com/dicepool-api

Dungeons & Dragons 5th-edition encounter-building maths as an API, computed locally and deterministically — the XP-budget and difficulty numbers a Dungeon Master balances a fight with. The budget endpoint sums the per-character XP thresholds from the DMG across the party — by party size and level, or a list of mixed levels — to give the easy, medium, hard and deadly budget for one encounter (a party of four 5th-level characters has thresholds of 1,000 / 2,000 / 3,000 / 4,400 XP), plus the total adventuring-day budget. The difficulty endpoint rates an encounter: it sums the monsters' XP, multiplies by the encounter multiplier for the number of monsters (×1.5 for two, ×2 for three to six, up to ×4 for fifteen or more), and compares the adjusted XP to the party thresholds — four 450-XP monsters against that party come to 3,600 adjusted XP, a hard fight. The carry endpoint gives the carrying capacity (Strength × 15, scaled by size), push/drag/lift and the encumbrance thresholds. Everything is computed locally and deterministically, so it is instant and private. Ideal for tabletop, virtual-tabletop, DM-tool and TTRPG app developers, encounter-builder and balance tools, and game-master education. Pure local computation — no key, no third-party service, instant. Uses the DMG tables. Live, nothing stored. 3 compute endpoints. For monster stats and spells use a D&D SRD data API.

api.oanor.com/dndencounter-api

完整的龙与地下城第五版系统参考文档作为API——法术、怪物、职业、子职业、种族、背景、装备、魔法物品、状态、特性、专长、技能以及完整的规则参考。按名称查找法术（例如火球术→3级塑能系，150英尺，8d6火焰伤害）或怪物属性（例如成年红龙→挑战等级17，AC 19，256生命值，传奇动作），列出并筛选任何资源类型（按等级或学派筛选法术，按挑战等级筛选怪物），或获取24个SRD类别中任何一个的完整详细信息。由开放的dnd5eapi.co数据集支持。非常适合角色构建器、虚拟桌面、遭遇和法术卡生成器、Discord机器人和自制工具。

api.oanor.com/dnd-api