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 setting to control execution behavior.

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.

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.

Market orders on thin markets can have significant slippage. Check the depth chart before placing large market orders.

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 for the full fee schedule.

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.

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 for encoding details.