The keeper
An optional worker that can buy tokens on the market and fill a bid in one atomic transaction when the trade is profitable.
#Swap and fill in one transaction
The keeper looks for bids that can be filled profitably by buying the token on the market first. It uses its own SOL for a 
Jupiter swap, then sells the tokens into the bid. The swap and the fill are built into a single transaction.
- 01Market swapKeeper buys tokens
- 02Fill the bidTokens → bidder
- 03Atomic resultBoth succeed or both revert
The bidder receives tokens at the bid's fixed price. The difference between the bid proceeds and the keeper's purchase and execution costs is the keeper's potential profit.
#Conditions for an attempt
The keeper needs a valid route, enough operating funds, a supported token, an unpaused bid and an expected return above the configured profit threshold. Transaction size, liquidity, slippage and changing quotes can prevent an attempt.
| Check | Purpose |
|---|---|
| Execution switch | The operator must enable keeper execution. The default is disabled. |
| Trade limit | Caps how much SOL the keeper can use in one trade. |
| Minimum profit | Requires a margin after seller fees, network fees and token account costs. |
| Simulation | Checks the assembled transaction before sending it. |