# Swaps

A swap on Biscotti exchanges one ERC-20 for another at the best available
price across every pool the protocol knows about.

## How a swap executes

:::steps
### Quote

The app quotes your trade against all candidate routes:

* **V3 pools** — each fee tier of each pair on the path (via `QuoterV2`)
* **Stable pools** — Curve-style pools for like-priced assets (via `get_dy`)
* **Multi-hop paths** — e.g. `TOKEN → USDC → EURC` when no direct pool exists

### Route selection

The [Smart Router](/smart-router) picks the route — or a **split** across
several routes — that maximizes your output after fees and price impact.

### Execution

The trade executes atomically through `BiscottiSmartRouter.multicall`. Either
every hop of every route succeeds, or the whole transaction reverts. Your
minimum-received amount (slippage tolerance) is enforced on-chain.
:::

## Fees

| Pool type | Swap fee | Goes to |
| --- | --- | --- |
| V3 pool | 0.05% / 0.30% / 1.00% depending on [fee tier](/concentrated-liquidity/fee-tiers) | In-range LPs |
| Stable pool | 0.04% (configurable per pool) | LPs, minus admin share |

Fees accrue to liquidity providers, not the protocol router — the Smart Router
itself charges nothing.

## Price impact vs. slippage

* **Price impact** is how much your own trade moves the pool price. Large
  trades in shallow pools have high impact; the UI warns you before you
  confirm.
* **Slippage tolerance** protects you from other people's trades landing
  before yours. If execution would return less than your minimum, the
  transaction reverts instead of filling badly.

:::tip[Stable pairs barely slip]
Swapping between like-priced assets (e.g. USDC ↔ EURC) routes through
[stable pools](/stable-pools) whose amplified curve keeps price impact near
zero even for large trades.
:::

## Exact input only

Biscotti quotes and executes **exact-input** trades: you specify how much you
sell, and the router guarantees a minimum you receive. Exact-output selectors
are deliberately absent from the router so a mis-encoded trade reverts loudly
rather than mis-executing. See [Smart Router](/smart-router) for the
rationale.