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

# Order Types

> Limit and market orders on Vela Exchange.

Vela supports two order types: **Limit** and **Market**. Both types can be combined with any [Time in Force](/trading/time-in-force) setting to control execution behavior.

<Tabs>
  <Tab title="Limit Orders">
    A limit order specifies both the quantity and the **maximum price** you are willing to pay (buy) or the **minimum price** you are willing to accept (sell).

    **Key properties:**

    * Will only execute at your specified price or better
    * Rests in the order book if it cannot fill immediately (with GTC)
    * Provides price certainty — you know the worst-case execution price
    * May not fill immediately, or at all, if the market doesn't reach your price

    **When to use limit orders:**

    * When the exact execution price matters to you
    * When you want to enter or exit a position at a specific level
    * When you are a market maker providing liquidity (combine with Post-Only TIF)
    * When market impact is a concern and you want to avoid paying the spread

    **Example — Limit Buy:**
    You want to buy 1 ETH but only at 3,200 USDC or lower. You place a limit buy at 3200 for 1 ETH. If the best ask is currently 3250, your order rests in the book. When a seller is willing to sell at 3200 or below, your order fills.

    **Example — Limit Sell:**
    You hold 2 ETH and want to sell if the price rises to 3,500 USDC. You place a limit sell at 3500 for 2 ETH. The order rests until a buyer arrives at that price or better.
  </Tab>

  <Tab title="Market Orders">
    A market order executes immediately at the best available prices in the order book. You specify only the quantity — the price is determined by whatever liquidity is available.

    **Key properties:**

    * Executes immediately (or is cancelled if no liquidity)
    * No price guarantee — you receive the best available price, which may include slippage
    * Useful when speed of execution matters more than price
    * Can result in multiple fills at different prices if walking the book

    **When to use market orders:**

    * When you need to enter or exit immediately regardless of price
    * When the spread is tight and slippage is minimal
    * When the order size is small relative to available depth

    **Slippage warning:**
    A market order walks the book from the best price outward until the quantity is filled. On a thin book, this can result in fills at significantly worse prices than the best bid/ask. Always check the depth chart before placing a large market order.

    **Example — Market Buy:**
    You place a market buy for 5 ETH. The order book has:

    * 2 ETH available at 3200 USDC
    * 2 ETH available at 3205 USDC
    * 3 ETH available at 3210 USDC

    Your order fills: 2 ETH at 3200, 2 ETH at 3205, 1 ETH at 3210. Average fill price: 3204 USDC.

    <Warning>
      Market orders on thin markets can have significant slippage. Check the depth chart before placing large market orders.
    </Warning>
  </Tab>
</Tabs>

## Comparison

| Feature              | Limit                       | Market                    |
| -------------------- | --------------------------- | ------------------------- |
| Price control        | Yes — specify max/min price | No — takes best available |
| Guaranteed execution | No — may not fill           | Yes — fills or cancels    |
| Rests in book        | Yes (with GTC)              | No — immediate only       |
| Slippage risk        | None (or bounded)           | Present on thin markets   |
| Compatible TIF       | GTC, IOC, FOK, Post-Only    | IOC only (implicit)       |
| Maker eligible       | Yes                         | No — always taker         |

## Order Type and Fees

Market makers (limit orders that rest in the book) receive a different fee treatment than market takers (market orders and aggressive limit orders that immediately match). See [Fees and Rebates](/trading/fees) for the full fee schedule.

<Tip>
  Using **Post-Only** Time in Force with a limit order guarantees you will always be a maker. The order is rejected if it would match immediately, protecting you from accidentally paying taker fees.
</Tip>

## Fixed-Point Price and Quantity

Prices and quantities submitted via the API are integers in fixed-point format scaled by **1,000,000**:

| Human-readable | API value    |
| -------------- | ------------ |
| 3200.00 USDC   | `3200000000` |
| 0.5 ETH        | `500000`     |
| 0.001 BTC      | `1000`       |

The UI handles this conversion automatically. If you're using the API directly, see [API Reference](/api-reference/http) for encoding details.