advanced
idle
results show up here. select some filters, then hit Search.
no seeds matched. remove or loosen a filter and search again.
| seed | act 1 map | neow offers | ancients | bosses |
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compose the Slay the Spire 2 run start you want and find every seed that matches. empty slots match anything. the search covers the whole seed space (4,294,967,296 runs) in your browser, no server involved.
| seed | act 1 map | neow offers | ancients | bosses |
|---|
SearchTheSpire is a free web-based seed finder tool for Slay the Spire 2. you compose the run start you want (character, Neow bonus, ancients, act 1 bosses, fights, events, shop contents) and it searches every possible seed for runs that meet those criteria. you can also paste a seed you already have into the inspect box to preview its run start.
every run starts with a seed. when you start a regular, unseeded run, the game generates a random string and hashes that string down to a 32-bit number, so there are exactly 4,294,967,296 distinct runs.
the game uses multiple random number generators, combined with the starting seed, to determine every random result over the course of a run. these generators always produce the same values in the same order, but different actions consume different numbers of rolls, which means that some kinds of rewards depend on the path you've taken to get there.
every combat reward - potion chance, potion dropped, gold amount, card reward rarity, card rewards, and even relic rarity - is determined by the same RNG stream. so anything that pulls from that stream along your path changes what you'll see next: whether you take 4 combats or 5 before your first elite, or whether you gorge or search in the room full of cheese, affects every reward roll after it.
this means that predicting some kinds of rewards (e.g. the act boss rewards) would require you to take a precise set of actions, including making certain event choices, by the time you've arrived at the boss. in my opinion, that's not very fun, and so i'm not planning on filters that only work if you play one precise route. this tool hides information that you do not explicitly filter on behind spoiler pills to keep some mystery in the run you ultimately play.
(note: you can filter on the shop relic slot, the third relic every merchant sells, because relic reward order is pre-determined by the seed; it's just the rarity that varies roll-by-roll. shop relics all have the same rarity and one appears in every shop, so there's no confounding RNG.)
small portions of StS2's RNG engine were re-implemented in Rust, using the game's own code as a reference. given a seed, this engine can reproduce certain rewards the game would grant without actually running the game.
that engine is compiled to WebAssembly and runs entirely in your browser. when you hit Search, a pool of workers splits the seed space into chunks, shuffles them, and checks run starts against your filters, millions per second. the entire seed space can be searched this way, and even a capped search gets a random and representative sample of matching seeds. checking a seed doesn't simulate a whole run; we only check exactly as many RNG calls as are needed to satisfy the specified predicates.
the engine is pinned against tests generated from the game's own code, and i personally check seeds in-game :)
copy a seed from the results, then in the game go to singleplayer and start a custom run, which has a seed field; paste the seed there. you must have beaten act 3 three times to unlock custom mode.
no. predictions here are for a plain seeded run with no modifiers. run modifiers consume random rolls in ways this tool doesn't model.