> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.avantisfi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Core Concepts

> Units, keys, execution routes, and receipts: the five things every page assumes.

## Human units everywhere

Every SDK method takes and returns human units. `100` means 100 USDC, `10` means 10x leverage, prices are plain decimals (`3500.5`). The SDK handles all on-chain scaling (1e6 for USDC, 1e10 for prices/leverage). Pass strings for exact decimals (`collateral="100.25"`).

## Two time bases

| Field                            | Unit                                  |
| -------------------------------- | ------------------------------------- |
| Intent `deadline` / `deadlineMs` | **milliseconds** (handled by the SDK) |
| Delegate `expiry_seconds`        | **seconds**                           |

## Keys: trader vs API key (delegate)

* **Trader key**: your wallet's own key. Can do everything.
* **API key (delegate)**: a separate key registered to your wallet with one signature (generate one with the [Avantis API Key Generator](https://delegate.avantisfi.com/)). Can trade, but can **never** withdraw funds, approve USDC, add delegates, or act on caller-scoped surfaces (referral, claims, LP vault).

Set `AVANTIS_TRADER_ADDRESS` when using an API key; leave it unset when using the trader key directly. See [Delegates](/account/delegates).

## Execution routes

The default is the **relayer**, which is gasless: no ETH, no RPC. `execution="direct"` signs and broadcasts EIP-1559 transactions through your own `rpc_url` instead. Full details in [Execution modes](/advanced/execution-modes).

One exception: `update_tp_sl` is intent-only in v2 and always goes through the relayer, even in direct mode.

## Pairs

Every method accepts a symbol or a pair index interchangeably: `"ETH/USD"`, `"eth-usd"`, or `1`.

## Receipts and fills

Write methods return an `ExecutionReceipt`:

| Field         | Meaning                                                                                            |
| ------------- | -------------------------------------------------------------------------------------------------- |
| `route`       | `batched-market`, `price-triggers`, `relayer-passthrough`, `twap-api`, `rpc`, or `txbuilder-relay` |
| `tx_hash`     | On-chain hash once settled (may be `None` with `wait=False`)                                       |
| `request_id`  | Relayer queue id (blitz relayer routes)                                                            |
| `tracking_id` | Batched-market lifecycle id (status replay handle)                                                 |
| `order_id`    | On-chain order id / twapId, when the API reports it                                                |

`wait=True` (default) follows the order until it settles or `relay_poll_timeout_s` elapses. On the batched-market route the receipt IS fill-aware: success means the terminal `MarketOrderExecuted` event arrived, and a protocol-declined fill raises `RelayError`. On the other relayer routes the receipt confirms your transaction landed, not that the operator filled the order.

<Tip>
  For position-level confirmation, poll `client.account.positions()` after a short delay, or subscribe to the [order event stream](/data/prices-and-streams).
</Tip>

```python theme={null}
receipt = await client.trade.market_open("ETH/USD", "long", collateral=100, leverage=10)
await asyncio.sleep(3)
positions = await client.account.positions()   # the fill shows up here
```

## Errors

Every failure raises a typed exception from `avantis_trader_sdk.errors`. See [Errors](/advanced/errors).