Order Types

Senticore is designed for professional order handling across spot, binary options, and prediction markets.

Test coverage

Every order type below has dedicated behavior test coverage and is included in continuous integration coverage gating. Randomized sequence fuzzing across supported order types runs regularly, asserting deterministic state across independent engine instances.

Time-in-force

Type	Behavior
GTC	Rests on the book until filled, cancelled, or expired
IOC	Fills immediately against available liquidity and cancels the remainder
FOK	Fills the entire quantity immediately or rejects
Post-only	Rests as maker liquidity; rejects if it would cross the spread

Modifiers

Modifier	Behavior
is_market	Market order; takes available liquidity
reduce_only	Outcome (YES/NO) markets only: can only reduce an existing position. Rejected on spot markets (reduce_only_invalid_side)
stp_mode	Self-trade prevention behavior
expires_at	Auto-cancel timestamp for eligible orders

Self-trade prevention

The engine default is cancel_taker. An account or credential default overrides the engine default, and an explicit per-order stp_mode overrides both.

stp_mode	Behavior on an otherwise executable self-cross
cancel_taker	Preserve the resting maker; cancel the incoming remainder
cancel_maker	Cancel the resting self-owned maker and continue matching
reject	Reject the incoming action without changing either order
skip_self	Skip self-owned makers and continue to external liquidity

Use the exact lowercase values above on JSON and BSL. FIX tag 7928 and FIXP use the documented numeric mapping. An unsupported value returns the stable invalid_stp_mode cause and the allowed values.

Post-only is evaluated before STP. A crossing post-only order is rejected with post_only_would_cross even when the maker belongs to the same account and the selected STP mode would normally skip or cancel that maker. This preserves the invariant that post-only never removes liquidity.

Conditional orders

Conditional orders trigger child orders based on market conditions.

The TypeScript SDK high-level local-signing helpers currently cover SpotPlaceOrder, OutcomePlaceOrder, Cancel, AmendOrder, SpotQuoteReplace, and QuoteReplace. Advanced algo and conditional actions are available as raw signed HTTP/BSL actions where enabled; construct and sign the raw action payload shown in Raw actions instead of calling non-existent sdk.placeAlgoOrder or sdk.placeConditionalOrder helpers.

Stop loss

{
  "PlaceConditionalOrder": {
    "market": 1,
    "book": "YES",
    "side": "Ask",
    "qty": 100000,
    "limit_price": 600000,
    "trigger_price": 610000,
    "trigger_direction": "at_or_below",
    "conditional_kind": "stop_loss",
    "reduce_only": true,
    "signed_trigger_order": {
      "payload": { "...": "pre-signed child order payload" },
      "signature": { "scheme": "EcdsaSecp256k1", "bytes": [1, 2, 3] }
    }
  }
}

Direction	Use case
at_or_below	Sell-side stop for downside protection
at_or_above	Buy-side stop or short-position protection

Take profit

{
  "PlaceConditionalOrder": {
    "market": 1,
    "book": "YES",
    "side": "Ask",
    "qty": 100000,
    "limit_price": 795000,
    "trigger_price": 800000,
    "trigger_direction": "at_or_above",
    "conditional_kind": "take_profit",
    "reduce_only": true,
    "signed_trigger_order": {
      "payload": { "...": "pre-signed child order payload" },
      "signature": { "scheme": "EcdsaSecp256k1", "bytes": [1, 2, 3] }
    }
  }
}

OCO

One-cancels-other links a take-profit and stop-loss path. Submit the first conditional order, then submit the second with linked_conditional_id set to the returned conditional id. When one triggers, the linked order is cancelled.

Algorithmic orders

Algorithmic orders execute over time according to a strategy.

For spot algo orders, omit book (or send null) and use the spot market id; YES/NO is outcome-market routing only. Conditional orders in the current raw schema remain outcome-book based and must not be presented as generic spot conditional orders.

Iceberg

{
  "PlaceAlgoOrder": {
    "market": 1,
    "book": "YES",
    "side": "Bid",
    "total_qty": 1000000,
    "limit_price": 510000,
    "strategy": {
      "kind": "iceberg",
      "display_qty": 100000
    }
  }
}

Behavior:

• Only the display quantity is visible at a time.
• A new slice posts as the visible slice fills.
• Cancelling the parent releases remaining reserved collateral.

TWAP

{
  "PlaceAlgoOrder": {
    "market": 1,
    "book": "YES",
    "side": "Bid",
    "total_qty": 1000000,
    "limit_price": 510000,
    "strategy": {
      "kind": "twap",
      "slice_qty": 100000,
      "interval_ms": 60000,
      "start_at": 1781190000000
    }
  }
}

Behavior:

• Slices are submitted on a fixed interval.
• The last slice is capped to remaining quantity.
• A stale or blocked child order prevents uncontrolled order spam.

VWAP

{
  "PlaceAlgoOrder": {
    "market": 1,
    "book": "YES",
    "side": "Bid",
    "total_qty": 1000000,
    "limit_price": 510000,
    "strategy": {
      "kind": "vwap",
      "participation_bps": 1000,
      "min_slice_qty": 100000
    }
  }
}

Behavior:

• Child size follows recent market volume.
• participationBps controls the target share of market volume.
• Execution pauses when observed volume is zero.

Validation rules

Rule	Behavior
Price tick	Price must align to the market tick size
Lot size	Quantity must align to lot size
Max quantity	Per-market cap (maxOrderQtyMicro on the market item, where set) is enforced
Open order cap	Per-account cap is enforced
Book depth cap	Prevents unbounded price-level growth
Minimum notional	Rejects dust orders
Price range (YES/NO books)	Price must be greater than zero and at most 1000000 (1.000 USDC) on every binary and prediction market; see Markets
Market lifecycle	New orders are accepted only while the market status is open and the action ts is before expiryTsMs

Tick size, lot size, native asset decimals, and minimum notional are market-definition data. Resolve them from GET /api/v1/public/exchange-info or GET /api/v1/public/markets; do not copy representative BTC/ETH/SOL values into an order client. See Markets for the live per-market values.

A BSL compact request is checked in two stages, and they fail differently:

1. Ingress checks cover the whole HTTP request. Shape, signature, timestamp skew, the single-account rule, the market lifecycle and expiry, the nonce window, rate limits and the ingress risk pre-check run before any action is sequenced. If one action fails, the whole request is rejected (ok: false, acceptedActions: 0, seqs: [], reason in error) and none of its actions runs.
2. After admission, each action is applied on its own. An action that fails in the engine (price above the outcome cap, tick/lot misalignment, quantity above maxOrderQtyMicro, post-only cross, insufficient USDC, base asset or YES/NO shares) is dropped with receipt status: dropped, applied: false and a detail text. Other actions in the same request are not affected.

A QuoteReplace / SpotQuoteReplace is one action, however many legs it has. If any leg fails, the whole action is rolled back and every one of its sequence numbers shows dropped with the same detail, so the bids and asks quoted in it do not rest either. Size asks below your free inventory, keep every leg inside the market rules, and put bids and asks in separate actions when inventory is uncertain. See Cancel-replace failure behavior.

Common rejection reasons

Error	Meaning
post_only_requires_passive_limit_order	Post-only order is marketable or not a passive limit
post_only_would_cross	Post-only order would cross the spread
insufficient_balance	Account lacks free balance for the order plus fee buffer
book_depth_exceeded	Order book depth cap reached
price_level_order_cap_exceeded	Per-price-level order cap reached
reduce_only_qty_exceeds_position	Reduce-only order would increase exposure
reduce_only_invalid_side	Reduce-only used on the wrong side or on a spot market
InsufficientShares	Ask on a YES/NO book without enough free shares; mint a complete set first (Split, 1 USDC → 1 YES + 1 NO). On a spot market it means an outcome-market envelope was sent by mistake
price above binary cap: PriceMicros(N)	YES/NO limit price above 1000000 (1.000 USDC). Applies to binary and prediction markets; 1000000 itself is accepted. No stable code assigned yet: machine-mapped as engine_rejected / ENGINE_REJECTED. Not retriable; clamp the price
market N lifecycle=S is not accepting new orders	Market status is not open (for example halted, closed, resolved_no). No stable code assigned yet. Stop quoting that market and re-read the catalog
market N expired for trading at T	Action ts is at or after the market's expiryTsMs, although status may still read open. No stable code assigned yet. Stop quoting that market
TRADING_HALTED	Venue-wide halt ("Trading is halted. Wait for trading to resume before retrying."); poll GET /api/v1/status (tradingHalted, expectedReopenMs) instead of retrying blindly