Live from the chain
The loop
From a swap to a proven digit, in one transaction.
π isn’t stored anywhere. Every digit is earned by a trade and derived on the spot — then anyone can recompute it to check our work.
You swap
Trade any size on the π pool. It’s an ordinary Uniswap v4 swap — same gas, same routing.
The hook fires
v4 routes execution into π’s afterSwap hook before the trade settles.
A digit is revealed
The next digit of π — committed onchain — is read in sequence and written to state.
It’s proven onchain
The digit and its index are committed to state. verify(n) returns it for anyone to check.
Uniswap v4 · the hook
A hook that fishes digits out of π.
v4 hooks let a pool run custom logic at points in a swap’s lifecycle. Ours mines a hook address with the afterSwap permission flag, so every completed trade hands control to the π contract.
Instead of reading a price, it advances a counter and pulls the next digit of π straight from the math. We use the Bailey–Borwein–Plouffe spigot — a formula that yields the n-th digit on its own, so the contract never has to store or recompute the ones before it.
- Lifecycle pointafterSwap
- DerivationBBP spigot · base-16
- State per digitindex · value · proof
- MemoryO(1) — no table
- Verificationverify(n) · permissionless
// fired by the PoolManager after every swap function afterSwap(...) external onlyPoolManager returns (bytes4, int128) { uint256 n = piIndex + 1; uint8 digit = PiSpigot.digitAt(n); // BBP _commit(n, digit); // → onchain state emit DigitDiscovered(n, digit, sender); piIndex = n; return (BaseHook.afterSwap.selector, 0); }