> For the complete documentation index, see [llms.txt](https://ocx.gitbook.io/ocx-doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ocx.gitbook.io/ocx-doc/ocx/getting-started/first-trade.md).

# first trade

This walkthrough covers buying `BTC-PERP` from both the UI and the API.

## From the UI

{% stepper %}
{% step %}

### Open the **Perps** page and select `BTC-PERP` from the market selector.

{% endstep %}

{% step %}

### Check the orderbook, mark price, and funding rate shown in the market header.

{% endstep %}

{% step %}

### In the order ticket:

* Choose **Limit** or **Market** order.
* Enter your **price** (limit only) and **size**.
* Pick a **time in force**: `GTC`, `IOC`, or `FOK`.
* Optionally enable **Post Only** (limit only — guarantees the order sits on the book as a maker).
  {% endstep %}

{% step %}

### Click **Buy / Long** or **Sell / Short**.

{% endstep %}

{% step %}

### Confirm the order preview showing the resulting position, initial margin, and estimated fees.

{% endstep %}
{% endstepper %}

The order appears under **Open Orders** or — if it executes immediately — under **Positions**.

## From the API

Before placing orders, make sure your `perps` bucket has collateral. See [Deposit USDC](broken://pages/69b82e7fcac3bbb5789a3ff3baa328e144d86672) for the transfer step.

{% stepper %}
{% step %}

### Preview the order

It's a good habit to preview every order so you know the margin impact before committing:

```http
POST /perps/orders/preview
Authorization: Bearer ocx_sk_...

{
  "marketId": "BTC-PERP",
  "side": "buy",
  "type": "limit",
  "price": "67000",
  "quantity": "0.1",
  "timeInForce": "gtc",
  "marginMode": "cross"
}
```

```json
{
  "approved": true,
  "reason": null,
  "marginImpact": {
    "initialMargin":     "100.50",
    "maintenanceMargin": "67.00"
  }
}
```

If `approved` is `false`, `reason` tells you why (usually `INSUFFICIENT_MARGIN`).
{% endstep %}

{% step %}

### Place the order

```http
POST /perps/orders
Authorization: Bearer ocx_sk_...

{
  "marketId": "BTC-PERP",
  "clientOrderId": "my-first-trade",
  "side": "buy",
  "type": "limit",
  "price": "67000",
  "quantity": "0.1",
  "timeInForce": "gtc",
  "marginMode": "cross"
}
```

```json
{
  "id": "01HW...",
  "userId": "01HW...",
  "marketId": "BTC-PERP",
  "clientOrderId": "my-first-trade",
  "side": "buy",
  "type": "limit",
  "price": "67000",
  "quantity": "0.1",
  "filledQuantity": "0",
  "status": "open",
  "marginMode": "cross",
  "createdAt": "2026-04-24T12:00:00Z",
  "updatedAt": "2026-04-24T12:00:00Z"
}
```

{% endstep %}

{% step %}

### Watch fills and position

```http
GET /perps/positions
```

```http
GET /perps/trades
```

For live updates, subscribe to the orderbook stream at `/perps/book-stream` (SSE) or the price stream at `/ws/perps/prices` (WebSocket). See [Streams](file:///7302513/api/streams.md).
{% endstep %}

{% step %}

### Cancel an open order

```http
POST /perps/orders/{id}/cancel
```

Or cancel all open orders on a market:

```http
POST /perps/orders/cancel-all
{ "marketId": "BTC-PERP" }
```

{% endstep %}
{% endstepper %}

## Order types at a glance

| Type     | Behavior                                                                               |
| -------- | -------------------------------------------------------------------------------------- |
| `limit`  | Rests on the book at your specified price. Fills at that price or better when matched. |
| `market` | Executes immediately against the best available price. Can partially fill.             |

| Time in force | Behavior                                                                           |
| ------------- | ---------------------------------------------------------------------------------- |
| `gtc`         | Good-til-cancelled. Rests until filled or cancelled.                               |
| `ioc`         | Immediate-or-cancel. Fills what it can immediately; the rest is cancelled.         |
| `fok`         | Fill-or-kill. Either fills completely at the limit price or is cancelled entirely. |

| Flag         | Behavior                                                              |
| ------------ | --------------------------------------------------------------------- |
| `postOnly`   | Order is cancelled if it would cross the book (guarantees maker fee). |
| `reduceOnly` | Order cannot increase your position — only reduce it.                 |

## What's next

* Learn how [Margin & Risk](file:///7302513/product/margin-and-risk.md) computes your requirements.
* Browse the full [Perpetuals Trading API](file:///7302513/api/perpetuals-trading.md).
* Connect a live bot with [API Keys](file:///7302513/authentication/api-keys.md).


---

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