1inch · edvardg · Apr 1, 2026 · Apr 3, 2026
diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@1inch/fusion-sdk",
-    "version": "2.4.6",
+    "version": "2.4.6-rc.1",
     "description": "1inch Fusion SDK",
     "author": "@1inch",
     "files": [

diff --git a/src/fusion-order/fusion-extension.ts b/src/fusion-order/fusion-extension.ts
@@ -15,6 +15,7 @@ import {Whitelist} from './whitelist/whitelist.js'
 import {SurplusParams} from './surplus-params.js'
 import {Fees, IntegratorFee, ResolverFee} from './fees/index.js'
 import {add0x} from '../utils.js'
+import {ZX} from '../constants.js'
 
 export class FusionExtension {
     /**
@@ -30,6 +31,7 @@ export class FusionExtension {
         public readonly surplus: SurplusParams,
         public readonly extra?: {
             makerPermit?: Interaction
+            preInteraction?: Interaction
             customReceiver?: Address
             fees?: Fees
         }
@@ -117,6 +119,11 @@ export class FusionExtension {
             ? Interaction.decode(extension.makerPermit)
             : undefined
 
+        const preInteraction =
+            extension.preInteraction !== ZX
+                ? Interaction.decode(extension.preInteraction)
+                : undefined
+
         assert(
             amountData.fees.integratorFee.value ===
                 interactionData.fees.integratorFee.value,
@@ -160,6 +167,7 @@ export class FusionExtension {
                 surplusParams,
                 {
                     makerPermit,
+                    preInteraction,
                     customReceiver,
                     fees: undefined
                 }
@@ -189,6 +197,7 @@ export class FusionExtension {
             surplusParams,
             {
                 makerPermit,
+                preInteraction,
                 fees,
                 customReceiver
             }
@@ -212,6 +221,10 @@ export class FusionExtension {
             )
         }
 
+        if (this.extra?.preInteraction) {
+            builder.withPreInteraction(this.extra.preInteraction)
+        }
+
         return builder.build()
     }
 

diff --git a/src/fusion-order/fusion-order.spec.ts b/src/fusion-order/fusion-order.spec.ts
@@ -3,6 +3,7 @@ import {
     Bps,
     MakerTraits,
     Extension,
+    Interaction,
     ProxyFactory
 } from '@1inch/limit-order-sdk'
 import {parseEther, parseUnits} from 'ethers'
@@ -791,3 +792,192 @@ describe('FusionOrder Native', () => {
         expect(nativeOrder.build().receiver).toEqual(settlementExt.toString())
     })
 })
+
+describe('FusionOrder preInteraction', () => {
+    it('should create order with preInteraction and set PRE_INTERACTION_CALL_FLAG in makerTraits', () => {
+        const extensionContract = new Address(
+            '0x2ad5004c60e16e54d5007c80ce329adde5b51ef5'
+        )
+
+        const preInteraction = new Interaction(
+            new Address('0x3a617c2fbaf8d7c58c793fbbd2d14eb4927876c1'),
+            '0xdeadbeef01020304'
+        )
+
+        const order = FusionOrder.new(
+            extensionContract,
+            {
+                makerAsset: new Address(
+                    '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c'
+                ),
+                takerAsset: new Address(
+                    '0xda7ad9dea9397cffddae2f8a052b82f1484252b3'
+                ),
+                makingAmount: 1983000000000000n,
+                takingAmount: 79052953622246027n,
+                maker: new Address('0x3a617c2fbaf8d7c58c793fbbd2d14eb4927876c1')
+            },
+            {
+                auction: new AuctionDetails({
+                    duration: 180n,
+                    startTime: 1673548149n,
+                    initialRateBump: 50000,
+                    points: [{coefficient: 20000, delay: 12}]
+                }),
+                whitelist: Whitelist.new(1673548139n, [
+                    {
+                        address: new Address(
+                            '0x00000000219ab540356cbb839cbe05303d7705fa'
+                        ),
+                        allowFrom: 0n
+                    }
+                ]),
+                surplus: SurplusParams.NO_FEE
+            },
+            {
+                preInteraction: preInteraction.encode()
+            }
+        )
+
+        const makerTraits = new MakerTraits(BigInt(order.build().makerTraits))
+
+        expect(makerTraits.hasPreInteraction()).toBe(true)
+    })
+
+    it('should not set PRE_INTERACTION_CALL_FLAG when no preInteraction', () => {
+        const extensionContract = new Address(
+            '0x2ad5004c60e16e54d5007c80ce329adde5b51ef5'
+        )
+
+        const order = FusionOrder.new(
+            extensionContract,
+            {
+                makerAsset: new Address(
+                    '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c'
+                ),
+                takerAsset: new Address(
+                    '0xda7ad9dea9397cffddae2f8a052b82f1484252b3'
+                ),
+                makingAmount: 1983000000000000n,
+                takingAmount: 79052953622246027n,
+                maker: new Address('0x3a617c2fbaf8d7c58c793fbbd2d14eb4927876c1')
+            },
+            {
+                auction: new AuctionDetails({
+                    duration: 180n,
+                    startTime: 1673548149n,
+                    initialRateBump: 50000,
+                    points: [{coefficient: 20000, delay: 12}]
+                }),
+                whitelist: Whitelist.new(1673548139n, [
+                    {
+                        address: new Address(
+                            '0x00000000219ab540356cbb839cbe05303d7705fa'
+                        ),
+                        allowFrom: 0n
+                    }
+                ]),
+                surplus: SurplusParams.NO_FEE
+            }
+        )
+
+        const makerTraits = new MakerTraits(BigInt(order.build().makerTraits))
+
+        expect(makerTraits.hasPreInteraction()).toBe(false)
+    })
+
+    it('should round-trip order with preInteraction via fromDataAndExtension', () => {
+        const extensionContract = new Address(
+            '0x2ad5004c60e16e54d5007c80ce329adde5b51ef5'
+        )
+
+        const preInteractionTarget = new Address(
+            '0x3a617c2fbaf8d7c58c793fbbd2d14eb4927876c1'
+        )
+        const preInteractionCalldata =
+            '0x0599a1fd1975848548e5b765925a935093a96ecc6f2ca216f77dcfd328b8a491'
+        const preInteraction = new Interaction(
+            preInteractionTarget,
+            preInteractionCalldata
+        )
+
+        const order = FusionOrder.new(
+            extensionContract,
+            {
+                makerAsset: new Address(
+                    '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c'
+                ),
+                takerAsset: new Address(
+                    '0xda7ad9dea9397cffddae2f8a052b82f1484252b3'
+                ),
+                makingAmount: 1983000000000000n,
+                takingAmount: 79052953622246027n,
+                maker: new Address('0x3a617c2fbaf8d7c58c793fbbd2d14eb4927876c1')
+            },
+            {
+                auction: new AuctionDetails({
+                    duration: 180n,
+                    startTime: 1673548149n,
+                    initialRateBump: 50000,
+                    points: [{coefficient: 20000, delay: 12}]
+                }),
+                whitelist: Whitelist.new(1673548139n, [
+                    {
+                        address: new Address(
+                            '0x00000000219ab540356cbb839cbe05303d7705fa'
+                        ),
+                        allowFrom: 0n
+                    }
+                ]),
+                surplus: SurplusParams.NO_FEE
+            },
+            {
+                preInteraction: preInteraction.encode()
+            }
+        )
+
+        const built = order.build()
+        const extension = order.extension
+
+        const restored = FusionOrder.fromDataAndExtension(
+            {
+                salt: built.salt,
+                maker: built.maker,
+                receiver: built.receiver,
+                makerAsset: built.makerAsset,
+                takerAsset: built.takerAsset,
+                makerTraits: built.makerTraits,
+                makingAmount: built.makingAmount,
+                takingAmount: built.takingAmount
+            },
+            extension
+        )
+
+        expect(restored.build().salt).toEqual(built.salt)
+        expect(restored.extension.encode()).toEqual(extension.encode())
+    })
+
+    it('should validate OKX order with preInteraction (real customer data)', () => {
+        const extensionHex =
+            '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'
+
+        const extension = Extension.decode(extensionHex)
+
+        expect(() => {
+            FusionOrder.fromDataAndExtension(
+                {
+                    maker: '0x3a617c2fbaf8d7c58c793fbbd2d14eb4927876c1',
+                    makerAsset: '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c',
+                    makerTraits:
+                        '69656178681823023809491920669288819567982727296017585526061607372909138935808',
+                    makingAmount: '1983000000000000',
+                    receiver: '0xb698362cc878094c406115efeeb13089b544e6c8',
+                    salt: '1084071965642925953405739669729447852001208220133',
+                    takerAsset: '0xda7ad9dea9397cffddae2f8a052b82f1484252b3',
+                    takingAmount: '79052953622246027'
+                },
+                extension
+            )
+        }).not.toThrow()
+    })
+})
diff --git a/src/fusion-order/fusion-order.ts b/src/fusion-order/fusion-order.ts
@@ -57,6 +57,9 @@ export class FusionOrder {
                 makerPermit: extra.permit
                     ? new Interaction(orderInfo.makerAsset, extra.permit)
                     : undefined,
+                preInteraction: extra.preInteraction
+                    ? Interaction.decode(extra.preInteraction)
+                    : undefined,
                 customReceiver: orderInfo.receiver,
                 fees: extra?.fees
             }
@@ -102,6 +105,10 @@ export class FusionOrder {
             makerTraits.enablePermit2()
         }
 
+        if (extra.preInteraction) {
+            makerTraits.enablePreInteraction()
+        }
+
         if (extra.nonce !== undefined) {
             makerTraits.withNonce(extra.nonce)
         }
@@ -393,6 +400,10 @@ export class FusionOrder {
                     extension.makerPermit === ZX
                         ? undefined
                         : Interaction.decode(extension.makerPermit).data,
+                preInteraction:
+                    extension.preInteraction === ZX
+                        ? undefined
+                        : extension.preInteraction,
                 unwrapWETH: makerTraits.isNativeUnwrapEnabled(),
                 orderExpirationDelay,
                 fees: extra?.fees,

diff --git a/src/fusion-order/types.ts b/src/fusion-order/types.ts
@@ -11,6 +11,13 @@ export type Extra = {
      */
     nonce?: bigint
     permit?: string
+    /**
+     * Encoded pre-interaction: target address (20 bytes) followed by calldata.
+     * Format matches `Interaction.encode()`: `0x{target}{calldata}`.
+     * When set, the PRE_INTERACTION_CALL_FLAG is enabled in makerTraits
+     * and the LOP contract calls IPreInteraction on the target before the swap.
+     */
+    preInteraction?: string
     /**
      * Default is true
      */