Order Types
Market orders, limit orders, and the order book
Overview
Vezta supports multiple order types depending on the underlying exchange and your trading tier. Understanding order types helps you control execution price, manage risk, and optimize your trading strategy.
Market Orders
A market order executes immediately at the best available price.
- When to use: You want to enter or exit a position right now and are willing to accept the current price.
- Advantage: Instant execution.
- Trade-off: On thin order books, large market orders may experience price impact (slippage).
Available on both Polymarket and Kalshi (via DFlow).
Limit Orders
A limit order lets you set the exact price you want to pay. Your order sits in the order book until another trader is willing to fill it at your price.
- When to use: You have a target entry price and are willing to wait for it.
- Advantage: Full price control.
- Trade-off: Your order may not fill if the market never reaches your price.
For example, if YES shares are currently at $0.65 but you only want to buy at $0.55, you place a limit order at $0.55.
Limit orders are Polymarket-only today. DFlow currently supports market orders (swaps) only -- limit orders are on DFlow's roadmap but not yet available. If you place a limit order on a Kalshi market, the order will be rejected.
The Order Book (Polymarket)
Polymarket uses a Central Limit Order Book (CLOB). The order book is a list of all open buy and sell orders at various prices.
Bid and Ask
- Bids are buy orders -- prices traders are willing to pay
- Asks are sell orders -- prices traders are willing to accept
- The spread is the gap between the highest bid and the lowest ask
A tighter spread means better liquidity and more efficient pricing. The order book visualization on the market detail page shows bid depth (green) and ask depth (red) so you can gauge available liquidity at each price level.
Price Impact
When you place a large order, it may consume multiple price levels in the order book. This is called price impact. For example, if you want to buy 10,000 YES shares but only 2,000 are available at $0.65, the remaining 8,000 may fill at progressively higher prices.
Vezta shows an estimated price impact before you confirm your order so there are no surprises.
Pro Order Types
The following order types are available in Pro mode:
| Order Type | Description | Source |
|---|---|---|
| Fill-and-Kill (FAK) | Fills as much as possible at your price, cancels the rest | Polymarket |
| Post Only | Adds liquidity only -- rejects if it would immediately fill | Polymarket |
| Fill-or-Kill (FOK) | Fills the entire order at your price or cancels completely | Polymarket |
| Good-til-Canceled (GTC) | Stays open until filled or manually canceled | Polymarket |
| Take Profit / Stop Loss | Automated exit orders triggered at specified price levels | Vezta (any exchange) |
| Sniper | Price-triggered automated entry | Vezta (any exchange) |
Pro order types map to the underlying exchange's capabilities. Polymarket-specific order types (FAK, FOK, GTC, Post Only) are only available for Polymarket markets. Kalshi-via-DFlow currently supports market orders only -- TP/SL and sniper orders work by placing market orders when the trigger condition fires.
Order Lifecycle
After you place an order, it moves through these states (Prisma OrderStatus enum):
- CREATED -- order validated and saved to database
- SUBMITTING -- being submitted to the exchange
- OPEN -- accepted by the exchange and resting on the book (limit only)
- PARTIALLY_FILLED -- some shares filled, rest still pending
- FILLED -- fully executed (terminal state)
- CANCELLING / CANCELLED -- in the process of being cancelled / cancelled
- REJECTED -- exchange rejected the order
- FAILED -- submission failed (network, validation, etc.)
You can track all your orders and their current status in the Portfolio page under the Order History tab. Real-time updates arrive via the user:orders WebSocket channel.
Trading Safety Infrastructure
Vezta has several safety nets running behind every order:
- Idempotency keys -- A SHA-256 hash of
userId:marketId:side:amount:5minBucketis stored in Redis with a 5-minute TTL, preventing duplicate orders on retry - Pending balance checks -- Balance validation subtracts the totals of
SUBMITTING/OPEN/PARTIALLY_FILLEDorders before approving a new one - Per-exchange circuit breaker -- If one exchange starts erroring, that route is opened for 5 minutes; orders auto-route to the healthy venue
- Adapter retry -- 3x retry with exponential backoff (4xx errors are not retried)
- Order reconciliation -- Orders stuck in
SUBMITTINGfor >2 minutes are flagged and resolved automatically - Kalshi maintenance window -- Orders are blocked Thursdays 3-5 AM ET (Kalshi's announced maintenance window)