Aster Swap.

An Aster Swap is a single signed transaction that exchanges one token for another through an automated liquidity pool rather than matching against another trader's order. Instead of a buyer and seller meeting at an agreed price, you trade against a pool that holds both assets, and the pool's own formula sets the rate based on how much of each token it currently holds. This is the same mechanism described in the automated market maker model that most on-chain exchanges use, and it is why a quote can move slightly between the moment you type an amount and the moment you sign.

Why no order book is involved

A traditional exchange needs a matching buyer and seller at the same price. An Aster Swap skips that requirement entirely: the pool itself is always the counterparty, so a trade executes instantly as long as the pool holds enough liquidity, even at 3am when order-book volume elsewhere would be thin.

What determines the exact rate

The rate you receive comes from the ratio of the two tokens sitting in the pool at the moment your transaction is processed, not a price feed from elsewhere. Larger trades shift that ratio more, which is why the size of your own order affects the price you get on the trade.

One transaction, not two

Selling and buying happen inside the same signed transaction. There is no separate step where you first sell for an intermediate asset — the swap contract handles the exchange and delivers the output token to your address in one pass.

Before anything else, Aster needs a connected wallet to see your balances and to request your signature later. Once connected, you pick the token you are selling and the token you want to receive — the interface fills in an estimated rate as soon as both sides of the pair are set. If the exact pair you want has thin liquidity, the interface may route the trade through an intermediate token automatically, which simply adds a second internal hop inside the same transaction.

An ERC-20 token cannot be pulled by any contract, including Aster's swap router, until you grant it permission. That permission is a separate signed message called an approval, and it only has to happen once per token per wallet.

Why approval exists at all

The approval step is a safety feature baked into the ERC-20 standard itself, not something specific to Aster. It stops a contract from moving your tokens without your explicit, visible consent, and you can read exactly what you are granting in your wallet's confirmation screen before you sign.

Limited versus unlimited allowance

Some wallets default to an unlimited allowance so you never approve that token again; others let you set an exact amount for just this trade. A limited allowance means a future exploit in an unrelated contract cannot drain more than what you approved, so it is the more conservative choice for a token you rarely trade.

Once both tokens are selected and an amount is entered, Aster shows a live quote: the exchange rate, the estimated price impact, and the minimum amount you will accept after slippage. Price impact is how much your own trade moves the pool's ratio — small for a well-funded pair, larger for a thin one — and it is separate from slippage tolerance, which is the buffer you allow for the rate shifting between signing and confirmation. Checking both numbers before you sign is the entire difference between a predictable swap and an unpleasant surprise.

Quote field	What it tells you	What to watch for
Exchange rate	Tokens received per token sold, right now	Compare against an external reference price
Price impact	How much your size moves the pool ratio	High impact signals thin liquidity for that pair
Minimum received	Worst-case output after slippage tolerance	Set tolerance tight for stable pairs, looser for volatile ones

When price impact runs high

A large price impact usually means the pool for that pair is shallow relative to your trade size. Splitting the order into smaller pieces, or routing through a deeper pair on a venue tracked by DefiLlama, often gets a better net result than pushing the whole amount through one thin pool.

Setting slippage tolerance correctly

Too tight a tolerance and a normal price tick between signing and confirming can fail your trade outright, wasting the gas you already spent. Too loose, and a sandwich attempt or a stale quote can fill you at a noticeably worse rate — a middle setting appropriate to the pair's usual volatility is the safer default.

Signing the confirmation sends your transaction to the network. The swap contract pulls your approved input token, runs the pool's pricing formula, sends the output token to your address, and updates the pool's reserves — all inside the same transaction, the way a standard exchange contract works as documented in Uniswap's developer docs, which describe the pooled-liquidity model Aster's own pools follow. Nothing is final until the transaction is mined; before that, it sits in the pending pool visible to anyone running a node.

The mechanics stay identical every time you trade, which is what makes the process predictable once you have done it once.

• Connect your wallet so Aster can read your balances and request a signature.
• Choose the token you're selling and the token you want to receive.
• Approve the input token if this is your first swap with it.
• Review the quoted rate, price impact, and minimum amount received.
• Sign to confirm; the swap contract executes the trade on-chain.
• Check the output token in your wallet once the transaction confirms.

Every Aster Swap produces a transaction hash you can look up on a block explorer such as Etherscan to confirm exactly what moved, what the gas cost was, and that the output token reached your address. If a swap fails, the most common causes are a slippage tolerance too tight for the current rate movement, an insufficient token approval, or not enough native currency in the wallet to cover gas. A failed transaction still consumes gas even though the trade itself did not execute, which is why double-checking the quote before signing is worth the extra few seconds.