How Kerb works

What this is

Kerb is a place to agree a price on a whole bag of a Robinhood Chain token with one other wallet. You post an ask (a bag for ETH) or a bid (ETH for a bag), public or private to one wallet. When someone takes it, tokens and ETH swap in one transaction, both legs or neither. No pool is touched, so no pool price moves.

Why not the pool

On Robinhood Chain most coins live in thin pools: a Pons bonding curve, then a full-range Uniswap v4 pool once they graduate. A pool prices each trade on a curve, so a sale that is large against it fills worse as it goes, and the price it leaves behind is what everyone sees on the chart. Two numbers come out of a big sale: the average fill, which the seller loses, and the chart move, which the market sees. On the desk both are zero.

How the sale is modelled

• Pons bonding curve, read on chain from the curve contract: its reserves, curve fee and creator tax, in Pons' own constant-product formula. Exact outside the first seconds' snipe tax.
• Graduated Pons pool on Uniswap v4, read on chain through the PoolManager (0x8366a39C…): price and liquidity. The Pons position is full range, so its virtual reserves are exact. Only the pool fee is counted, not the Pons hook fee, so real fills are a little worse than shown.
• Any other pool DEX Screener lists for the coin: constant product with half its USD value on each side. An estimate, labelled as one.

A sale is cut into 400 slices and each goes to the venue that pays most for it at that moment, the way an aggregator routes. The chart move is the deepest venue's price after the sale against before. Coins come from the Pons factory (0x7eD598Bc…): every ETH-paired coin that graduated, ranked by the ETH in its pool, plus the deepest curves launched in the last week.

Asks, bids, private offers

• An ask locks your tokens in the desk and names a total in ETH. Fee-on-transfer and rebasing tokens are refused at the deposit.
• A bid locks your ETH and names an amount of a token. A holder sends the tokens straight to you; the desk never holds them.
• A private offer names one wallet. The contract refuses a fill from anyone else.
• An offer stands 1 hour to 7 days (30 at most on the contract), may allow partial fills down to a smallest fill, and can be cancelled any time. Partial fills round so they always add up to the exact total.

What you sign

Ordinary transactions to the desk contract, nothing off chain. To sell: one approval for exactly the bag, then postAsk. To bid: postBid with the ETH attached. To take an ask: takeAsk with the price plus fee, to the wei. To take a bid: an approval for exactly the tokens, then takeBid. There is no server key, no signature to a backend, and no allowance left behind beyond what you approve.

Where funds sit

In your wallet until you post. Then only the escrow of that offer sits in the desk contract, and only three things can move it: a fill on the terms you set, your cancel, or a reclaim after expiry. A cancel or a reclaim pays the maker and nobody else, whoever sends it. The contract keeps no balance of its own: fees go straight to the treasury inside the fill.

Fees

Who you trust

• The contract, 0x87D17826A3178fBc151EC460AA6dA440d6e7Cd43 on Robinhood Chain. Its admin can change only where fees go. It cannot touch an escrow, pause fills or change the fee.
• Not audited. It has its own Foundry tests, including fuzzing and attacks (reentrancy, tax tokens, wallets that refuse ETH), and a mainnet-fork test with a live Pons coin, but no outside audit.
• Market data. Curve and pool reserves are read on chain; names, 24h change and non-Pons pools come from DEX Screener; holders from Blockscout. When they are wrong, an estimate is wrong.

Risks

• The other side may know more than you. Someone who wants out of a bag quietly may know why.
• A price set now can be far from the market later. Use an expiry you can watch.
• A wallet that refuses ETH cannot be paid, so its asks cannot fill. It can still cancel.

This edition

The desk runs on Robinhood Chain (4663). Its source is verified, exact match, on Sourcify.

$KERB is the desk's token. It is not live yet.