GitHub · by Jarrod Watts

jev-trader

A trading bot that places an order in every 300 ms block.

Jarrod Watts

@jarrodwatts

I built a trading bot with Jev! Jev decides if it should "buy" or "sell", given the price feed of an asset pair, and executes real trades. It uses Monad to place the orders on Kuru's on-chain order book in every 300ms block. Demo link → jev-trader.vercel.app

Sep 16, 2026 · 5.2K likesOpen on X

Jarrod Watts gives Jev the price feed of an asset pair, and Jev answers buy or sell. The bot then places real orders on Kuru’s on-chain order book on Monad, in every 300 ms block.

It is a market-making loop, not a directional bet. Every block the order it posts is post-only, one tick inside the touch, replacing the previous one in a single batch update that also cancels everything resting. Fills arrive when someone else’s taker order hits it, so the bot earns the spread instead of paying it. The question put to Jev each block is about the move over a horizon of 100 blocks, roughly 30 seconds, and the answer is buy or sell with probabilities attached.

Every block event the server streams carries the whole state: the mid, best bid and ask, the spread in basis points, the decision with its probabilities and its latency in milliseconds, the quote with its transaction hash and gas, the resting size, the position and the running totals — including what has been spent on Jev calls against what has been spent on gas. That comparison is the interesting one, and it is published rather than described.

Two details make it honest about a real chain. `hold` appears only when the model missed the block, flagged `late`, and nothing was posted. And because live sends are fired and forgotten, the block event carries the intent rather than the outcome: the receipt lands a block or two later as its own event, becoming placed, reverted or, after ten blocks with no receipt, lost. With no private key it dry-runs against the real book with simulated fills, and the default model is a momentum heuristic stand-in until you set Jev explicitly.