How a fill is simulated

1. Quote at click. The visible price on the page is merged with DexScreener. Agreement within 3% → high confidence; over 10% → trading pauses. Sudden jumps (>50% in 2 s), thin liquidity and pulled liquidity also pause trading.
2. Latency. A log-normal delay per profile, seeded by the order id so it can be replayed.
3. Re-quote and slippage check. If the price moved past your tolerance, the trade fails and the priority + base fee are charged (the tip is not).
4. Price impact. pump.fun curves use virtual reserves (30 SOL × 1.073 B tokens at launch); AMM pools use reported reserves; concentrated-liquidity pools are approximated and labelled. Optional: Jupiter route quotes.
5. Partial fills when an order would take more than 20% of the pool's SOL side.
6. Fees. Axiom 1%, priority fee, tip, 5000-lamport base fee.
7. Accounting. 40-digit decimal arithmetic, average cost including fees; an invariant check runs on every property-test step.

Not modelled: exact route splitting, concentrated-liquidity tick depth, live priority-fee auctions, real congestion, token transfer taxes. Paper results do not predict real results.