diff --git a/.changeset/selfish-turkeys-knock.md b/.changeset/selfish-turkeys-knock.md
new file mode 100644
index 0000000..0b6ce18
--- /dev/null
+++ b/.changeset/selfish-turkeys-knock.md
@@ -0,0 +1,5 @@
+---
+"@across-protocol/app-sdk": patch
+---
+
+Add integratorId to getSwapQuote action
diff --git a/packages/sdk/package.json b/packages/sdk/package.json
index 341bf86..fe69721 100644
--- a/packages/sdk/package.json
+++ b/packages/sdk/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@across-protocol/app-sdk",
-  "version": "0.4.0",
+  "version": "0.4.1",
   "main": "./dist/index.js",
   "type": "module",
   "description": "The official SDK for integrating Across bridge into your dapp.",
@@ -63,4 +63,4 @@
   "peerDependencies": {
     "viem": "^2.31.2"
   }
-}
\ No newline at end of file
+}
diff --git a/packages/sdk/src/actions/getSwapQuote.ts b/packages/sdk/src/actions/getSwapQuote.ts
index 8ce18df..c794fdd 100644
--- a/packages/sdk/src/actions/getSwapQuote.ts
+++ b/packages/sdk/src/actions/getSwapQuote.ts
@@ -33,6 +33,11 @@ export type GetSwapQuoteParams = Omit<
   slippage?: number;
   appFee?: number;
   actions?: Action[];
+  /**
+   * [Optional] Integrator identifier to be forwarded to the swap API so it can
+   * append the integrator tag to the final deposit calldata when applicable.
+   */
+  integratorId?: string;
   /**
    * [Optional] The logger to use.
    */
diff --git a/packages/sdk/src/client.ts b/packages/sdk/src/client.ts
index bc38852..12ce434 100644
--- a/packages/sdk/src/client.ts
+++ b/packages/sdk/src/client.ts
@@ -661,6 +661,7 @@ export class AcrossClient {
       const quote = await getSwapQuote({
         ...params,
         skipOriginTxEstimation: true,
+        integratorId: params?.integratorId ?? this.integratorId,
         logger: params?.logger ?? this.logger,
         apiUrl: params?.apiUrl ?? this.apiUrl,
       });
diff --git a/packages/sdk/src/utils/hex.ts b/packages/sdk/src/utils/hex.ts
index ecd0547..068c7c0 100644
--- a/packages/sdk/src/utils/hex.ts
+++ b/packages/sdk/src/utils/hex.ts
@@ -1,6 +1,7 @@
 import { Address, concat, Hex, isAddress, isHex, padHex } from "viem";
 
 export const DOMAIN_CALLDATA_DELIMITER = "0x1dc0de";
+export const SWAP_CALLDATA_MARKER = "0x73c0de";
 
 export function tagIntegratorId(integratorId: Hex, txData: Hex) {
   assertValidIntegratorId(integratorId);
@@ -14,6 +15,25 @@ export function getIntegratorDataSuffix(integratorId: Hex) {
   return concat([DOMAIN_CALLDATA_DELIMITER, integratorId]);
 }
 
+export function hasIntegratorIdAppended(
+  calldata: Hex,
+  integratorId: Hex,
+  options: {
+    isSwap?: boolean;
+  } = {
+    isSwap: false,
+  },
+): boolean {
+  const integratorIdSuffix = getIntegratorDataSuffix(integratorId);
+  const swapSuffix = SWAP_CALLDATA_MARKER;
+  // swap/approval first appends the integratorId, then the swap marker
+  const suffix = options.isSwap
+    ? concat([integratorIdSuffix, swapSuffix])
+    : integratorIdSuffix;
+
+  return calldata.endsWith(suffix.slice(2));
+}
+
 export function isValidIntegratorId(integratorId: string) {
   return (
     isHex(integratorId) &&
diff --git a/packages/sdk/test/unit/actions/getSwapQuote.test.ts b/packages/sdk/test/unit/actions/getSwapQuote.test.ts
index 6e330e8..892bf8a 100644
--- a/packages/sdk/test/unit/actions/getSwapQuote.test.ts
+++ b/packages/sdk/test/unit/actions/getSwapQuote.test.ts
@@ -1,7 +1,9 @@
 import { assert, assertType, describe, test } from "vitest";
 import { type SwapApprovalApiResponse } from "../../../src/api/swap-approval.js";
 import { getSwapQuote } from "../../../src/actions/getSwapQuote.js";
-import { parseEther } from "viem";
+import { Hex, parseEther } from "viem";
+import { hasIntegratorIdAppended } from "../../../src/utils/hex.js";
+import { mainnetTestClient } from "../../common/sdk.js";
 
 // Mainnet WETH
 const inputToken = {
@@ -68,4 +70,68 @@ describe("getSwapQuote", () => {
     assert(quote, "No swap quote returned for the provided parameters");
     assertType<SwapApprovalApiResponse>(quote);
   });
+
+  test("swap approval calldata has integrator id appended", async () => {
+    const integratorId: Hex = "0xdead";
+
+    const quote = await getSwapQuote({
+      amount: parseEther(inputAmount),
+      route: {
+        originChainId: 1,
+        inputToken: inputToken.address,
+        destinationChainId: 10,
+        outputToken: outputToken.address,
+      },
+      depositor: testRecipient,
+      recipient: testRecipient,
+      integratorId,
+    });
+
+    assert(quote.swapTx, "swapTx missing in swap approval response");
+    let data: Hex;
+    if ("eip712" in quote.swapTx) {
+      data = quote.swapTx.swapTx.data as Hex;
+    } else {
+      const simple = quote.swapTx as { data: string };
+      data = simple.data as Hex;
+    }
+
+    assert(
+      hasIntegratorIdAppended(data, integratorId, {
+        isSwap: true,
+      }),
+      "Expected swap calldata to have integrator id suffix",
+    );
+  });
+
+  test("client injects integratorId when omitted", async () => {
+    const quote = await mainnetTestClient.getSwapQuote({
+      amount: parseEther(inputAmount),
+      route: {
+        originChainId: 1,
+        inputToken: inputToken.address,
+        destinationChainId: 10,
+        outputToken: outputToken.address,
+      },
+      depositor: testRecipient,
+      recipient: testRecipient,
+      // no integrator ID
+    });
+
+    assert(quote.swapTx, "swapTx missing in swap approval response");
+    let data: Hex;
+    if ("eip712" in quote.swapTx) {
+      data = quote.swapTx.swapTx.data as Hex;
+    } else {
+      const simple = quote.swapTx as { data: string };
+      data = simple.data as Hex;
+    }
+
+    // Client default integratorId is 0xdead when not configured explicitly
+    const expectedIntegratorId: Hex = "0xdead";
+    assert(
+      hasIntegratorIdAppended(data, expectedIntegratorId, { isSwap: true }),
+      "Expected swap calldata to include client's integrator id when omitted in params",
+    );
+  });
 });