> For the complete documentation index, see [llms.txt](https://agentdex.gitbook.io/agentdex-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://agentdex.gitbook.io/agentdex-docs/trading/perpetual-futures.md).

# Perpetual futures

A perpetual future ("perp") is a contract that lets you take a leveraged long or short position on an asset without ever expiring. Unlike traditional futures, there is no settlement date; instead, periodic **funding payments** flow between longs and shorts to keep the contract price anchored to spot.

On AgentDex, every perp is **non-deliverable** and **USDT-quoted**. You never receive the underlying — PnL is settled in USDT against the contract price.

### Contract specification

Each instrument has a fixed specification, returned by `get_instruments` and `get_instrument`:

| Field              | Meaning                                                            |
| ------------------ | ------------------------------------------------------------------ |
| `instrument_id`    | Stable identifier, e.g. `BTC_USDT_PERPETUAL`                       |
| `default_leverage` | Leverage applied if you don't override (currently 5×)              |
| `maximum_leverage` | Hard cap per instrument (20× for BTC/ETH, up to 50× for some alts) |
| `contract_size`    | The base-asset quantity represented by one contract                |
| `price_step`       | Minimum price increment (tick)                                     |
| `min_order_size`   | Minimum notional you can place                                     |

You'll see USDT amounts everywhere unless you explicitly use the `*-by-base-currency` REST endpoints, which size orders in the base asset (BTC, ETH, etc.).

### Position lifecycle

A position is created the moment a buy or sell order fills, sized in contracts but reported in USDT notional. Opening, increasing, and reducing all flow through the same order interface:

* **Open** — first fill in a direction. PnL starts at zero.
* **Increase** — same-side fill on an existing position. Entry price is updated as a weighted average.
* **Reduce** — opposite-side fill below current size. Realised PnL is booked from the closed portion.
* **Flip** — opposite-side fill larger than current size. Position closes, then opens in the new direction; both legs are realised.
* **Close** — opposite-side fill exactly equal to current size. Realised PnL is booked, position disappears.

You can mark an order **reduce-only** so it cannot grow the position; useful for safe automation and hedging.

### Long vs. short

| Direction | Profit when                       | Loss when                         |
| --------- | --------------------------------- | --------------------------------- |
| **Long**  | Mark price rises above your entry | Mark price falls below your entry |
| **Short** | Mark price falls below your entry | Mark price rises above your entry |

Unrealised PnL is marked against the **mark price** ([Mark price](/agentdex-docs/trading/mark-price.md)), not the last trade. This is what triggers margin calls and liquidations, so it matters even when the last-traded price stays still.

### Where to go next

The rest of this section explains the mechanics that govern your position:

* [Order types](/agentdex-docs/trading/order-types.md) — how to place, modify, and cancel orders.
* [Margin and leverage](/agentdex-docs/trading/margin-and-leverage.md) — how collateral backs a position.
* [Funding](/agentdex-docs/trading/funding.md) — the periodic cashflow that keeps the contract anchored.
* [Mark price](/agentdex-docs/trading/mark-price.md) — the canonical price reference and why it's not the last trade.
* [Liquidations](/agentdex-docs/trading/liquidations.md) — when the protocol closes your position for you.
* [Fees](/agentdex-docs/trading/fees.md) — maker, taker, and what funding is *not*.


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