Order Types

Alphio supports market, limit, and trigger orders across all 3 trade rails, with reduce-only and post-only modifiers.

---

1. Market order

A market order executes immediately at the best available price on the order book — speed over price.

• Used when you want to enter or exit a position right now and accept whatever fill price the book offers.
• Fill behavior — fills the full quantity as fast as the venue can route it, walking the book if needed.
• Risk — in thin or fast markets you may pay meaningful slippage vs the last-traded price. For perpetuals, slippage is capped by the rail; for stocks it depends on broker routing.

On Hyperliquid Perpetuals, market orders are accepted with order_type: MARKET; the rail can fill at mid ± an internal slippage tolerance when no explicit price is provided.

---

2. Limit order

A limit order executes only at your specified price or better — price over speed.

• Used when you have a target entry / exit and are willing to wait (or miss the fill).
• Fill behavior — may fill partially, fully, or not at all, depending on whether the market reaches your price.
• Time-in-force — Hyperliquid limit orders carry a time_in_force flag: GTC (good-till-canceled), IOC (immediate-or-cancel), or ALO (add-liquidity-only / post-only).

On Stock Trading, limit orders sit at the broker until filled or canceled, subject to that broker's session and routing rules.

---

3. Trigger order

A trigger order waits for the market to cross a price threshold, then fires as a market or limit order.

Sub-types Alphio surfaces:

Sub-type	Trigger condition	Fires as
Limit trigger	Price crosses threshold	Limit order at a separate limit price
Stop trigger	Price crosses threshold	Market order
Stop-loss	Adverse price move past threshold	Market (close position to cap loss)
Take-profit	Favorable price move past threshold	Market (close position to lock gain)

On Hyperliquid the trigger order is expressed as order_type: STOP_LOSS or TAKE_PROFIT with a trigger_price; is_trigger_market controls whether it fires as market or limit when triggered.

Trigger orders are useful both as standalone risk management (place a stop-loss on an existing position) and as conditional entries (only buy if price breaks above resistance).

---

4. Order modifiers

Two flags can be combined with the order types above:

• Reduce Only — the order can only reduce an existing position, never flip or grow it. If your position is already smaller than the order size at fill time, the rail caps the fill to the remaining position. Used for safely placing exits without risk of accidentally opening a new opposite-side position.
• Post Only — the order is rejected if it would execute immediately as a taker. Forces maker-only behavior to capture maker rebates / avoid taker fees. On Hyperliquid this maps to time_in_force: ALO (Add-Liquidity-Only).

Reduce Only is most useful on perpetuals where you may flip sides; Post Only is most useful when you care about fee tier.

---

5. TP / SL attached to position

When opening a position (on perpetuals especially), the Trade Modal lets you attach a take-profit and / or stop-loss at the same time. These are stored as trigger orders linked to the position and fire automatically once price crosses the threshold.

You can also attach TP / SL after the fact to an open position from the positions panel — without canceling and replacing the original entry order.

The attached TP / SL respects the position size: if you partially close manually, the linked TP / SL is scaled down to the remaining size.

---

6. Rail-specific support

Not every rail supports every order type. The table below summarizes what's available where.

Order type	Stock Trading (SnapTrade)	Hyperliquid Perpetuals	Polymarket Prediction Markets
Market	Yes	Yes	Yes (effectively — crosses the order book)
Limit	Yes	Yes (GTC / IOC / ALO)	Yes (signed CLOB order)
Trigger (stop / TP / SL)	:::warning Broker-dependent — confirm with your broker	Yes (TAKE_PROFIT / STOP_LOSS with trigger_price)	:::warning TBC
Reduce Only	N/A (no perp concept)	Yes	N/A
Post Only	:::warning Broker-dependent	Yes (ALO)	:::warning TBC
Attached TP / SL	:::warning Broker-dependent	Yes	:::warning TBC

warning

Exact per-broker support for trigger orders on Stock Trading varies by upstream broker (SnapTrade routes to many). Exact support for advanced order types on Polymarket prediction markets is being finalized. The Trade Modal is authoritative — it only renders order types the active rail actually supports.