About & rights
An independent fan project, built to be checked
SLAY2 is a free, noncommercial strategy companion for Slay the Spire 2. It is not affiliated with, endorsed by or sponsored by Mega Crit. The game, its name and its content belong to their owners.
Purpose
What it is for
The aim is to make decisions in the Spire easier to reason about: exact odds where the rules are known, an explainable card advisor where they are not, and a public ledger of what has and has not been verified. Nothing here plays the game for you and nothing reads the game while it runs.
It covers the current main build, v0.107.1, solo play, ascension 0 to 10 and the five characters. The beta build is deliberately not supported until its rules have been checked, because Early Access changes numbers between patches. See Evidence & methods for every rule and its status.
Content
What is on this site, and what is not
On this site
- Original code, mathematics, tests and interface design.
- Factual identifiers for cards: canonical id, display name, class, rarity, cost and type, with provenance.
- Our own short role tags such as “attack”, “block” or “draw”, written by us.
- Aggregated results from our own simulator experiments, always labelled as simulator output.
- A hand-drawn SVG illustration made for this site.
Not on this site
- Game art, icons, audio, fonts, logos or card frames.
- Card, relic, potion or event text, flavour text or descriptions, from the game or from any site.
- Bulk dumps or mirrors of extracted game data, decompiled code or game files.
- AI-generated imagery presented as art.
- Accounts, advertising, trackers, cookies or paid features.
Provenance
Where the rules come from
Each rule on the methods page carries an evidence class. The strongest is the behaviour of the shipped game build, checked by reading its logic for facts and constants only. After that come official statements and community wikis, which are cited with attribution and never copied. Our own exact arithmetic is then tested four independent ways before a number is shown.
Nothing read from the game's code or from third-party databases is redistributed: what we keep is the fact (for example, a constant and where it was found), not the text. If a rights holder objects to a source, the rules that depend on it are marked so and can be re-supported by other evidence.
Simulator experiments run on a third-party research simulator whose agreement with the live game has not been verified. Its results are shown only as simulator output with their sample size and known gaps, never as a promise about your next run.
Privacy
What stays in your browser
Your run (character, deck, recorded rewards) is stored only in this browser's local storage, and in files you choose to export. There are no accounts, no cookies and no analytics or tracking scripts, and the pages do not send your run anywhere. Clearing your site data, or using “New run”, removes it. Import and export are plain JSON you can read.
The public calculation endpoints under /api/v1 compute from the request you send and store nothing. They keep a short-lived, in-memory request counter per connecting address so one client cannot flood them; it is never written to disk and is best-effort.
Open decisions
What is deliberately still undecided
- License for SLAY2’s own code
- Not chosen yet, so for now all rights are reserved. A permissive or a noncommercial license will be picked by the owner.
- Money
- None. No ads, paywall, donations or sponsorship. Any change would need legal review and the rights holder’s confirmation first.
- A mod for the live game
- Not started. It has different rights and fairness questions from a website, so it is a separate decision.
- Live-game verification
- Simulator-to-game parity needs a licensed copy of the game and a reviewed bridge. Until then it is listed as unverified.
Corrections
Found a mistake?
No public contact channel has been configured for this deployment yet. When one is, it will appear here. Until then, treat anything marked “unverified” or “heuristic” as exactly that.