diff --git a/src/core/order-coordinator.ts b/src/core/order-coordinator.ts
index da0aea0..25b8464 100644
--- a/src/core/order-coordinator.ts
+++ b/src/core/order-coordinator.ts
@@ -1,6 +1,13 @@
 import type { ExchangeAdapter } from "../exchanges/adapter";
-import type { AsterOrder, CreateOrderParams } from "../exchanges/types";
-import { roundDownToTick, roundQtyDownToStep, formatPriceToString } from "../utils/math";
+import type { AsterOrder } from "../exchanges/types";
+import {
+  routeCloseOrder,
+  routeLimitOrder,
+  routeMarketOrder,
+  routeStopOrder,
+  routeTrailingStopOrder,
+} from "../exchanges/order-router";
+import { roundDownToTick, roundQtyDownToStep } from "../utils/math";
 import { isUnknownOrderError } from "../utils/errors";
 import { isOrderPriceAllowedByMark } from "../utils/strategy";
 
@@ -146,25 +153,30 @@ export async function placeOrder(
   if (isOperating(locks, type)) return;
   const priceNum = Number(price);
   if (!enforceMarkPriceGuard(side, priceNum, guard, log, "限价单")) return;
-  const priceTick = opts?.priceTick ?? 0.1;
   const qtyStep = opts?.qtyStep ?? 0.001;
-  const params: CreateOrderParams = {
-    symbol,
-    side,
-    type,
-    quantity: roundQtyDownToStep(amount, qtyStep),
-    price: priceNum, // 直接使用字符串转换的数字，不再格式化
-    timeInForce: "GTX",
-  };
-  if (reduceOnly) params.reduceOnly = "true";
+  const rawQuantity = Math.abs(amount);
+  const roundedQuantity = roundQtyDownToStep(rawQuantity, qtyStep);
+  const quantity = roundedQuantity > 0 ? roundedQuantity : rawQuantity;
+  if (quantity <= 0) {
+    log("error", "限价单数量无效，跳过下单");
+    return;
+  }
   if (!opts?.skipDedupe) {
     await deduplicateOrders(adapter, symbol, openOrders, locks, timers, pendings, type, side, log);
   }
   lockOperating(locks, timers, pendings, type, log);
   try {
-    const order = await adapter.createOrder(params);
+    const order = await routeLimitOrder({
+      adapter,
+      symbol,
+      side,
+      quantity,
+      price: priceNum,
+      timeInForce: "GTX",
+      reduceOnly: reduceOnly ? true : undefined,
+    });
     pendings[type] = String(order.orderId);
-    log("order", `挂限价单: ${side} @ ${params.price} 数量 ${params.quantity} reduceOnly=${reduceOnly}`);
+    log("order", `挂限价单: ${side} @ ${priceNum} 数量 ${quantity} reduceOnly=${reduceOnly}`);
     return order;
   } catch (err) {
     unlockOperating(locks, timers, pendings, type);
@@ -194,19 +206,25 @@ export async function placeMarketOrder(
   if (isOperating(locks, type)) return;
   if (!enforceMarkPriceGuard(side, guard?.expectedPrice ?? null, guard, log, "市价单")) return;
   const qtyStep = opts?.qtyStep ?? 0.001;
-  const params: CreateOrderParams = {
-    symbol,
-    side,
-    type,
-    quantity: roundQtyDownToStep(amount, qtyStep),
-  };
-  if (reduceOnly) params.reduceOnly = "true";
+  const rawQuantity = Math.abs(amount);
+  const roundedQuantity = roundQtyDownToStep(rawQuantity, qtyStep);
+  const quantity = roundedQuantity > 0 ? roundedQuantity : rawQuantity;
+  if (quantity <= 0) {
+    log("error", "市价单数量无效，跳过下单");
+    return;
+  }
   await deduplicateOrders(adapter, symbol, openOrders, locks, timers, pendings, type, side, log);
   lockOperating(locks, timers, pendings, type, log);
   try {
-    const order = await adapter.createOrder(params);
+    const order = await routeMarketOrder({
+      adapter,
+      symbol,
+      side,
+      quantity,
+      reduceOnly: reduceOnly ? true : undefined,
+    });
     pendings[type] = String(order.orderId);
-    log("order", `市价单: ${side} 数量 ${params.quantity} reduceOnly=${reduceOnly}`);
+    log("order", `市价单: ${side} 数量 ${quantity} reduceOnly=${reduceOnly}`);
     return order;
   } catch (err) {
     unlockOperating(locks, timers, pendings, type);
@@ -248,29 +266,32 @@ export async function placeStopLossOrder(
   }
   const priceTick = opts?.priceTick ?? 0.1;
   const qtyStep = opts?.qtyStep ?? 0.001;
-
-  const params: CreateOrderParams = {
-    symbol,
-    side,
-    type,
-    quantity: roundQtyDownToStep(quantity, qtyStep),
-    stopPrice: roundDownToTick(stopPrice, priceTick),
-    // Always mark reduce-only semantics; some exchanges (e.g. Aster) ignore this on STOP
-    reduceOnly: "true",
-    // Some exchanges prefer explicit close-position semantics; gateways will normalize
-    closePosition: "true",
-    timeInForce: "GTC",
-    // GRVT requires triggerType to match side semantics: BUY -> TAKE_PROFIT, SELL -> STOP_LOSS
-    triggerType: side === "BUY" ? "TAKE_PROFIT" : "STOP_LOSS",
-  };
+  const normalizedStop = roundDownToTick(stopPrice, priceTick);
+  const rawQuantity = Math.abs(quantity);
+  const roundedQuantity = roundQtyDownToStep(rawQuantity, qtyStep);
+  const normalizedQty = roundedQuantity > 0 ? roundedQuantity : rawQuantity;
+  if (normalizedQty <= 0) {
+    log("error", "止损单数量无效，跳过下单");
+    return;
+  }
 
   // Avoid forcing price for STOP_MARKET globally; keep this exchange-specific in gateways
   await deduplicateOrders(adapter, symbol, openOrders, locks, timers, pendings, type, side, log);
   lockOperating(locks, timers, pendings, type, log);
   try {
-    const order = await adapter.createOrder(params);
+    const order = await routeStopOrder({
+      adapter,
+      symbol,
+      side,
+      quantity: normalizedQty,
+      stopPrice: normalizedStop,
+      timeInForce: "GTC",
+      reduceOnly: true,
+      closePosition: true,
+      triggerType: side === "BUY" ? "TAKE_PROFIT" : "STOP_LOSS",
+    });
     pendings[type] = String(order.orderId);
-    log("stop", `挂止损单: ${side} STOP_MARKET @ ${params.stopPrice}`);
+    log("stop", `挂止损单: ${side} STOP_MARKET @ ${normalizedStop}`);
     return order;
   } catch (err) {
     unlockOperating(locks, timers, pendings, type);
@@ -299,27 +320,38 @@ export async function placeTrailingStopOrder(
 ): Promise<AsterOrder | undefined> {
   const type = "TRAILING_STOP_MARKET";
   if (isOperating(locks, type)) return;
+  if (!adapter.supportsTrailingStops()) {
+    log("error", "当前交易所不支持动态止盈单");
+    return;
+  }
   if (!enforceMarkPriceGuard(side, activationPrice, guard, log, "动态止盈单")) return;
   const priceTick = opts?.priceTick ?? 0.1;
   const qtyStep = opts?.qtyStep ?? 0.001;
-  const params: CreateOrderParams = {
-    symbol,
-    side,
-    type,
-    quantity,
-    reduceOnly: "true",
-    activationPrice: roundDownToTick(activationPrice, priceTick),
-    callbackRate,
-    timeInForce: "GTC",
-  };
+  const normalizedActivation = roundDownToTick(activationPrice, priceTick);
+  const rawQuantity = Math.abs(quantity);
+  const roundedQuantity = roundQtyDownToStep(rawQuantity, qtyStep);
+  const normalizedQty = roundedQuantity > 0 ? roundedQuantity : rawQuantity;
+  if (normalizedQty <= 0) {
+    log("error", "动态止盈单数量无效，跳过下单");
+    return;
+  }
   await deduplicateOrders(adapter, symbol, openOrders, locks, timers, pendings, type, side, log);
   lockOperating(locks, timers, pendings, type, log);
   try {
-    const order = await adapter.createOrder(params);
+    const order = await routeTrailingStopOrder({
+      adapter,
+      symbol,
+      side,
+      quantity: normalizedQty,
+      activationPrice: normalizedActivation,
+      callbackRate,
+      timeInForce: "GTC",
+      reduceOnly: true,
+    });
     pendings[type] = String(order.orderId);
     log(
       "order",
-      `挂动态止盈单: ${side} activation=${params.activationPrice} callbackRate=${callbackRate}`
+      `挂动态止盈单: ${side} activation=${normalizedActivation} callbackRate=${callbackRate}`
     );
     return order;
   } catch (err) {
@@ -349,18 +381,26 @@ export async function marketClose(
   if (isOperating(locks, type)) return;
   if (!enforceMarkPriceGuard(side, guard?.expectedPrice ?? null, guard, log, "市价平仓")) return;
 
-  const params: CreateOrderParams = {
-    symbol,
-    side,
-    type,
-    quantity,
-    reduceOnly: "true",
-  };
-  
+  const qtyStep = opts?.qtyStep;
+  const rawQuantity = Math.abs(quantity);
+  const normalizedQtyRaw = qtyStep != null ? roundQtyDownToStep(rawQuantity, qtyStep) : rawQuantity;
+  const normalizedQty = normalizedQtyRaw > 0 ? normalizedQtyRaw : rawQuantity;
+  if (normalizedQty <= 0) {
+    log("error", "市价平仓数量无效，跳过下单");
+    return;
+  }
+
   await deduplicateOrders(adapter, symbol, openOrders, locks, timers, pendings, type, side, log);
   lockOperating(locks, timers, pendings, type, log);
   try {
-    const order = await adapter.createOrder(params);
+    const order = await routeCloseOrder({
+      adapter,
+      symbol,
+      side,
+      quantity: normalizedQty,
+      reduceOnly: true,
+      closePosition: true,
+    });
     pendings[type] = String(order.orderId);
     log("close", `市价平仓: ${side}`);
   } catch (err) {
diff --git a/src/exchanges/aster/order.ts b/src/exchanges/aster/order.ts
new file mode 100644
index 0000000..fdad4e7
--- /dev/null
+++ b/src/exchanges/aster/order.ts
@@ -0,0 +1,101 @@
+import type { AsterOrder, CreateOrderParams } from "../types";
+import type {
+  BaseOrderIntent,
+  ClosePositionIntent,
+  LimitOrderIntent,
+  MarketOrderIntent,
+  StopOrderIntent,
+  TrailingStopOrderIntent,
+} from "../order-schema";
+import { toStringBoolean } from "../order-schema";
+
+function applyCommonFields(params: CreateOrderParams, intent: BaseOrderIntent): CreateOrderParams {
+  if (params.quantity === undefined) {
+    params.quantity = intent.quantity;
+  }
+  if (params.timeInForce === undefined && intent.timeInForce) {
+    params.timeInForce = intent.timeInForce;
+  }
+  if (intent.reduceOnly !== undefined) {
+    params.reduceOnly = toStringBoolean(intent.reduceOnly);
+  }
+  if (intent.closePosition !== undefined) {
+    params.closePosition = toStringBoolean(intent.closePosition);
+  }
+  return params;
+}
+
+export async function createLimitOrder(intent: LimitOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "LIMIT",
+      quantity: intent.quantity,
+      price: intent.price,
+      timeInForce: intent.timeInForce ?? "GTX",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createMarketOrder(intent: MarketOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createStopOrder(intent: StopOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "STOP_MARKET",
+      quantity: intent.quantity,
+      stopPrice: intent.stopPrice,
+      timeInForce: intent.timeInForce ?? "GTC",
+      triggerType: intent.triggerType,
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createTrailingStopOrder(intent: TrailingStopOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "TRAILING_STOP_MARKET",
+      quantity: intent.quantity,
+      activationPrice: intent.activationPrice,
+      callbackRate: intent.callbackRate,
+      timeInForce: intent.timeInForce ?? "GTC",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createClosePositionOrder(intent: ClosePositionIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      reduceOnly: "true",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
diff --git a/src/exchanges/backpack/order.ts b/src/exchanges/backpack/order.ts
new file mode 100644
index 0000000..0e31e8e
--- /dev/null
+++ b/src/exchanges/backpack/order.ts
@@ -0,0 +1,88 @@
+import type { AsterOrder, CreateOrderParams } from "../types";
+import type {
+  BaseOrderIntent,
+  ClosePositionIntent,
+  LimitOrderIntent,
+  MarketOrderIntent,
+  StopOrderIntent,
+  TrailingStopOrderIntent,
+} from "../order-schema";
+import { toStringBoolean } from "../order-schema";
+
+function applyCommonFields(params: CreateOrderParams, intent: BaseOrderIntent): CreateOrderParams {
+  if (params.quantity === undefined) {
+    params.quantity = intent.quantity;
+  }
+  if (params.timeInForce === undefined && intent.timeInForce) {
+    params.timeInForce = intent.timeInForce;
+  }
+  if (intent.reduceOnly !== undefined) {
+    params.reduceOnly = toStringBoolean(intent.reduceOnly);
+  }
+  if (intent.closePosition !== undefined) {
+    params.closePosition = toStringBoolean(intent.closePosition);
+  }
+  return params;
+}
+
+export async function createLimitOrder(intent: LimitOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "LIMIT",
+      quantity: intent.quantity,
+      price: intent.price,
+      timeInForce: intent.timeInForce ?? "GTX",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createMarketOrder(intent: MarketOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createStopOrder(intent: StopOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "STOP_MARKET",
+      quantity: intent.quantity,
+      stopPrice: intent.stopPrice,
+      timeInForce: intent.timeInForce ?? "GTC",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createTrailingStopOrder(_intent: TrailingStopOrderIntent): Promise<AsterOrder> {
+  throw new Error("Backpack exchange does not support trailing stop orders");
+}
+
+export async function createClosePositionOrder(intent: ClosePositionIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      reduceOnly: "true",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
diff --git a/src/exchanges/grvt/order.ts b/src/exchanges/grvt/order.ts
new file mode 100644
index 0000000..ac875b3
--- /dev/null
+++ b/src/exchanges/grvt/order.ts
@@ -0,0 +1,92 @@
+import type { AsterOrder, CreateOrderParams } from "../types";
+import type {
+  BaseOrderIntent,
+  ClosePositionIntent,
+  LimitOrderIntent,
+  MarketOrderIntent,
+  StopOrderIntent,
+  TrailingStopOrderIntent,
+} from "../order-schema";
+import { toStringBoolean } from "../order-schema";
+
+function applyCommonFields(params: CreateOrderParams, intent: BaseOrderIntent): CreateOrderParams {
+  if (params.quantity === undefined) {
+    params.quantity = intent.quantity;
+  }
+  if (params.timeInForce === undefined && intent.timeInForce) {
+    params.timeInForce = intent.timeInForce;
+  }
+  if (intent.reduceOnly !== undefined) {
+    params.reduceOnly = toStringBoolean(intent.reduceOnly);
+  }
+  if (intent.closePosition !== undefined) {
+    params.closePosition = toStringBoolean(intent.closePosition);
+  }
+  return params;
+}
+
+export async function createLimitOrder(intent: LimitOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "LIMIT",
+      quantity: intent.quantity,
+      price: intent.price,
+      timeInForce: intent.timeInForce ?? "GTX",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createMarketOrder(intent: MarketOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createStopOrder(intent: StopOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "STOP_MARKET",
+      quantity: intent.quantity,
+      stopPrice: intent.stopPrice,
+      timeInForce: intent.timeInForce ?? "GTC",
+      triggerType: intent.triggerType ?? (intent.side === "BUY" ? "TAKE_PROFIT" : "STOP_LOSS"),
+      closePosition: toStringBoolean(intent.closePosition ?? true),
+      reduceOnly: toStringBoolean(intent.reduceOnly ?? true),
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createTrailingStopOrder(_intent: TrailingStopOrderIntent): Promise<AsterOrder> {
+  throw new Error("GRVT exchange does not support trailing stop orders");
+}
+
+export async function createClosePositionOrder(intent: ClosePositionIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      reduceOnly: "true",
+      closePosition: toStringBoolean(intent.closePosition ?? true),
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
diff --git a/src/exchanges/lighter/order.ts b/src/exchanges/lighter/order.ts
new file mode 100644
index 0000000..899b157
--- /dev/null
+++ b/src/exchanges/lighter/order.ts
@@ -0,0 +1,93 @@
+import type { AsterOrder, CreateOrderParams } from "../types";
+import type {
+  BaseOrderIntent,
+  ClosePositionIntent,
+  LimitOrderIntent,
+  MarketOrderIntent,
+  StopOrderIntent,
+  TrailingStopOrderIntent,
+} from "../order-schema";
+import { toStringBoolean } from "../order-schema";
+
+function applyCommonFields(params: CreateOrderParams, intent: BaseOrderIntent): CreateOrderParams {
+  if (params.quantity === undefined) {
+    params.quantity = intent.quantity;
+  }
+  if (params.timeInForce === undefined && intent.timeInForce) {
+    params.timeInForce = intent.timeInForce;
+  }
+  if (intent.reduceOnly !== undefined) {
+    params.reduceOnly = toStringBoolean(intent.reduceOnly);
+  }
+  if (intent.closePosition !== undefined) {
+    params.closePosition = toStringBoolean(intent.closePosition);
+  }
+  return params;
+}
+
+export async function createLimitOrder(intent: LimitOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "LIMIT",
+      quantity: intent.quantity,
+      price: intent.price,
+      timeInForce: intent.timeInForce ?? "GTC",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createMarketOrder(intent: MarketOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      timeInForce: intent.timeInForce ?? "IOC",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createStopOrder(intent: StopOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "STOP_MARKET",
+      quantity: intent.quantity,
+      stopPrice: intent.stopPrice,
+      timeInForce: intent.timeInForce ?? "GTC",
+      reduceOnly: toStringBoolean(intent.reduceOnly ?? true),
+      closePosition: toStringBoolean(intent.closePosition ?? true),
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createTrailingStopOrder(_intent: TrailingStopOrderIntent): Promise<AsterOrder> {
+  throw new Error("Lighter exchange does not support trailing stop orders");
+}
+
+export async function createClosePositionOrder(intent: ClosePositionIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      reduceOnly: "true",
+      closePosition: toStringBoolean(intent.closePosition ?? true),
+      timeInForce: intent.timeInForce ?? "IOC",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
diff --git a/src/exchanges/order-router.ts b/src/exchanges/order-router.ts
new file mode 100644
index 0000000..ef3395d
--- /dev/null
+++ b/src/exchanges/order-router.ts
@@ -0,0 +1,118 @@
+import type { ExchangeAdapter } from "./adapter";
+import type { AsterOrder } from "./types";
+import type {
+  BaseOrderIntent,
+  ClosePositionIntent,
+  LimitOrderIntent,
+  MarketOrderIntent,
+  StopOrderIntent,
+  TrailingStopOrderIntent,
+} from "./order-schema";
+import * as asterOrders from "./aster/order";
+import * as backpackOrders from "./backpack/order";
+import * as grvtOrders from "./grvt/order";
+import * as lighterOrders from "./lighter/order";
+import * as paradexOrders from "./paradex/order";
+
+type ExchangeKey = "aster" | "backpack" | "grvt" | "lighter" | "paradex";
+
+interface ExchangeOrderHandlers {
+  limit(intent: LimitOrderIntent): Promise<AsterOrder>;
+  market(intent: MarketOrderIntent): Promise<AsterOrder>;
+  stop(intent: StopOrderIntent): Promise<AsterOrder>;
+  trailingStop?: (intent: TrailingStopOrderIntent) => Promise<AsterOrder>;
+  close(intent: ClosePositionIntent): Promise<AsterOrder>;
+}
+
+const handlerMap: Record<ExchangeKey, ExchangeOrderHandlers> = {
+  aster: {
+    limit: asterOrders.createLimitOrder,
+    market: asterOrders.createMarketOrder,
+    stop: asterOrders.createStopOrder,
+    trailingStop: asterOrders.createTrailingStopOrder,
+    close: asterOrders.createClosePositionOrder,
+  },
+  backpack: {
+    limit: backpackOrders.createLimitOrder,
+    market: backpackOrders.createMarketOrder,
+    stop: backpackOrders.createStopOrder,
+    trailingStop: backpackOrders.createTrailingStopOrder,
+    close: backpackOrders.createClosePositionOrder,
+  },
+  grvt: {
+    limit: grvtOrders.createLimitOrder,
+    market: grvtOrders.createMarketOrder,
+    stop: grvtOrders.createStopOrder,
+    trailingStop: grvtOrders.createTrailingStopOrder,
+    close: grvtOrders.createClosePositionOrder,
+  },
+  lighter: {
+    limit: lighterOrders.createLimitOrder,
+    market: lighterOrders.createMarketOrder,
+    stop: lighterOrders.createStopOrder,
+    trailingStop: lighterOrders.createTrailingStopOrder,
+    close: lighterOrders.createClosePositionOrder,
+  },
+  paradex: {
+    limit: paradexOrders.createLimitOrder,
+    market: paradexOrders.createMarketOrder,
+    stop: paradexOrders.createStopOrder,
+    trailingStop: paradexOrders.createTrailingStopOrder,
+    close: paradexOrders.createClosePositionOrder,
+  },
+};
+
+const knownExchanges: ExchangeKey[] = ["aster", "backpack", "grvt", "lighter", "paradex"];
+
+function normalizeExchangeId(value: string | undefined | null): string | undefined {
+  if (!value) return undefined;
+  return value.trim().toLowerCase();
+}
+
+function resolveExchangeKey(adapter: ExchangeAdapter): ExchangeKey {
+  const fromEnv = normalizeExchangeId(process.env.TRADE_EXCHANGE ?? process.env.EXCHANGE);
+  const candidates = [fromEnv, normalizeExchangeId(adapter.id)];
+  for (const candidate of candidates) {
+    if (!candidate) continue;
+    if ((knownExchanges as string[]).includes(candidate)) {
+      return candidate as ExchangeKey;
+    }
+  }
+  throw new Error(
+    `Unsupported exchange for order routing: ${candidates.filter(Boolean).join(", ") || "unknown"}`
+  );
+}
+
+function getHandlers(intent: BaseOrderIntent): ExchangeOrderHandlers {
+  const exchangeKey = resolveExchangeKey(intent.adapter);
+  const handlers = handlerMap[exchangeKey];
+  if (!handlers) {
+    throw new Error(`Order handlers not implemented for exchange: ${exchangeKey}`);
+  }
+  return handlers;
+}
+
+export function routeLimitOrder(intent: LimitOrderIntent): Promise<AsterOrder> {
+  return getHandlers(intent).limit(intent);
+}
+
+export function routeMarketOrder(intent: MarketOrderIntent): Promise<AsterOrder> {
+  return getHandlers(intent).market(intent);
+}
+
+export function routeStopOrder(intent: StopOrderIntent): Promise<AsterOrder> {
+  return getHandlers(intent).stop(intent);
+}
+
+export function routeTrailingStopOrder(intent: TrailingStopOrderIntent): Promise<AsterOrder> {
+  const handlers = getHandlers(intent);
+  if (!handlers.trailingStop) {
+    throw new Error("Trailing stop orders are not supported by the current exchange");
+  }
+  return handlers.trailingStop(intent);
+}
+
+export function routeCloseOrder(intent: ClosePositionIntent): Promise<AsterOrder> {
+  return getHandlers(intent).close(intent);
+}
+
diff --git a/src/exchanges/order-schema.ts b/src/exchanges/order-schema.ts
new file mode 100644
index 0000000..5712af4
--- /dev/null
+++ b/src/exchanges/order-schema.ts
@@ -0,0 +1,42 @@
+import type { ExchangeAdapter } from "./adapter";
+import type { OrderSide, TimeInForce } from "./types";
+
+export interface BaseOrderIntent {
+  adapter: ExchangeAdapter;
+  symbol: string;
+  side: OrderSide;
+  quantity: number;
+  reduceOnly?: boolean;
+  closePosition?: boolean;
+  timeInForce?: TimeInForce | "GTX";
+}
+
+export interface LimitOrderIntent extends BaseOrderIntent {
+  price: number;
+}
+
+export interface MarketOrderIntent extends BaseOrderIntent {
+  expectedPrice?: number | null;
+}
+
+export interface StopOrderIntent extends BaseOrderIntent {
+  stopPrice: number;
+  triggerType?: "UNSPECIFIED" | "TAKE_PROFIT" | "STOP_LOSS";
+}
+
+export interface TrailingStopOrderIntent extends BaseOrderIntent {
+  activationPrice: number;
+  callbackRate: number;
+}
+
+export interface ClosePositionIntent extends BaseOrderIntent {
+  expectedPrice?: number | null;
+}
+
+export type ExchangeOrderType = "limit" | "market" | "stop" | "trailingStop" | "close";
+
+export function toStringBoolean(value: boolean | undefined): "true" | "false" | undefined {
+  if (value === undefined) return undefined;
+  return value ? "true" : "false";
+}
+
diff --git a/src/exchanges/paradex/gateway.ts b/src/exchanges/paradex/gateway.ts
index b164bce..236bfd0 100644
--- a/src/exchanges/paradex/gateway.ts
+++ b/src/exchanges/paradex/gateway.ts
@@ -602,6 +602,9 @@ export class ParadexGateway {
       // Only omit amount for MARKET close-position orders; STOP requires explicit size
       const shouldOmitAmount = isClosePosition && type === "market";
       const amountArg: any = shouldOmitAmount ? undefined : amount;
+      if (!shouldOmitAmount && amountArg != null && extraParams.size === undefined) {
+        extraParams.size = amountArg.toString();
+      }
       const order = (await this.exchange.createOrder(
         symbol,
         type,
diff --git a/src/exchanges/paradex/order.ts b/src/exchanges/paradex/order.ts
new file mode 100644
index 0000000..351a23b
--- /dev/null
+++ b/src/exchanges/paradex/order.ts
@@ -0,0 +1,93 @@
+import type { AsterOrder, CreateOrderParams } from "../types";
+import type {
+  BaseOrderIntent,
+  ClosePositionIntent,
+  LimitOrderIntent,
+  MarketOrderIntent,
+  StopOrderIntent,
+  TrailingStopOrderIntent,
+} from "../order-schema";
+import { toStringBoolean } from "../order-schema";
+
+function applyCommonFields(params: CreateOrderParams, intent: BaseOrderIntent): CreateOrderParams {
+  if (params.quantity === undefined) {
+    params.quantity = intent.quantity;
+  }
+  if (params.timeInForce === undefined && intent.timeInForce) {
+    params.timeInForce = intent.timeInForce;
+  }
+  if (intent.reduceOnly !== undefined) {
+    params.reduceOnly = toStringBoolean(intent.reduceOnly);
+  }
+  if (intent.closePosition !== undefined) {
+    params.closePosition = toStringBoolean(intent.closePosition);
+  }
+  return params;
+}
+
+export async function createLimitOrder(intent: LimitOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "LIMIT",
+      quantity: intent.quantity,
+      price: intent.price,
+      timeInForce: intent.timeInForce ?? "GTC",
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createMarketOrder(intent: MarketOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      timeInForce: intent.timeInForce,
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createStopOrder(intent: StopOrderIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "STOP_MARKET",
+      quantity: intent.quantity,
+      stopPrice: intent.stopPrice,
+      price: intent.stopPrice,
+      timeInForce: intent.timeInForce ?? "GTC",
+      reduceOnly: toStringBoolean(intent.reduceOnly ?? true),
+      closePosition: toStringBoolean(intent.closePosition ?? true),
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
+
+export async function createTrailingStopOrder(_intent: TrailingStopOrderIntent): Promise<AsterOrder> {
+  throw new Error("Paradex exchange does not support trailing stop orders");
+}
+
+export async function createClosePositionOrder(intent: ClosePositionIntent): Promise<AsterOrder> {
+  const params: CreateOrderParams = applyCommonFields(
+    {
+      symbol: intent.symbol,
+      side: intent.side,
+      type: "MARKET",
+      quantity: intent.quantity,
+      reduceOnly: "true",
+      closePosition: toStringBoolean(intent.closePosition ?? true),
+      timeInForce: intent.timeInForce,
+    },
+    intent
+  );
+  return intent.adapter.createOrder(params);
+}
diff --git a/tests/order-coordinator.test.ts b/tests/order-coordinator.test.ts
index 4104b97..667d5d4 100644
--- a/tests/order-coordinator.test.ts
+++ b/tests/order-coordinator.test.ts
@@ -1,4 +1,4 @@
-import { describe, expect, it, vi } from "vitest";
+import { describe, expect, it, vi, beforeEach, afterAll } from "vitest";
 import type { ExchangeAdapter } from "../src/exchanges/adapter";
 import type { AsterOrder } from "../src/exchanges/types";
 import type { OrderLockMap, OrderTimerMap, OrderPendingMap } from "../src/core/order-coordinator";
@@ -12,6 +12,9 @@ import {
   unlockOperating,
 } from "../src/core/order-coordinator";
 
+const originalTradeExchange = process.env.TRADE_EXCHANGE;
+const originalExchange = process.env.EXCHANGE;
+
 const baseOrder: AsterOrder = {
   orderId: 1,
   clientOrderId: "client",
@@ -47,6 +50,16 @@ function createMockExchange(overrides: Partial<ExchangeAdapter> = {}): ExchangeA
 }
 
 describe("order-coordinator", () => {
+  beforeEach(() => {
+    process.env.TRADE_EXCHANGE = "aster";
+    process.env.EXCHANGE = undefined;
+  });
+
+  afterAll(() => {
+    process.env.TRADE_EXCHANGE = originalTradeExchange;
+    process.env.EXCHANGE = originalExchange;
+  });
+
   it("deduplicates orders by type and side", async () => {
     const adapter = createMockExchange();
     const locks: OrderLockMap = {};