diff --git a/README.md b/README.md
index d94e2d2..67249e5 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ Don't hesitate to reach out or submit pull requests with missing aggregators ada
 - [Li.Fi](https://li.fi/) `stable` `tested`
 - [Squid Router](https://www.squidrouter.com/) `stable` `tested`
 - [Socket](https://socket.tech/) `stable` `tested`
+- [Sifi](https://sifi.org/) `untested`
 
 ### Liquidity
 - [1inch](https://1inch.io/) `stable` `tested`
@@ -101,6 +102,7 @@ async function getTransactionRequests(): TransactionRequest[] {
 - [0x](https://github.com/AstrolabFinance/swapper/blob/main/src/ZeroX/index.ts)
 - [KyberSwap](https://github.com/AstrolabFinance/swapper/blob/main/src/KyberSwap/index.ts)
 - [ParaSwap](https://github.com/AstrolabFinance/swapper/blob/main/src/ParaSwap/index.ts)
+- [Sifi](https://github.com/AstrolabFinance/swapper/blob/main/src/Sifi/index.ts)
 
 ### Swapper Contract
 
diff --git a/src/Sifi/index.ts b/src/Sifi/index.ts
new file mode 100644
index 0000000..8de1134
--- /dev/null
+++ b/src/Sifi/index.ts
@@ -0,0 +1,87 @@
+import { ITransactionRequestWithEstimate } from "../types";
+import qs from "qs";
+import { ISwapperParams, validateQuoteParams } from "../types";
+
+// Sifi specific types
+interface IQuote {
+  // NOTE: No fields have been added since these are never accessed
+}
+
+interface IQuoteParams {
+  fromChain: number;
+  fromToken: string;
+  toChain?: number;
+  toToken: string;
+  fromAmount: string;
+  disablePermit?: number;
+}
+
+const ROUTER_ADDRESS = "0x65c49E9996A877d062085B71E1460fFBe3C4c5Aa";
+const apiRoot = "https://api.sifi.org/v1/";
+
+export const routerByChainId: { [id: number]: string } = {
+  1: ROUTER_ADDRESS,
+  10: ROUTER_ADDRESS,
+  56: ROUTER_ADDRESS,
+  137: ROUTER_ADDRESS,
+  8453: ROUTER_ADDRESS,
+  42161: ROUTER_ADDRESS,
+  43114: ROUTER_ADDRESS,
+};
+
+const convertParams = (o: ISwapperParams): IQuoteParams => ({
+  fromChain: o.inputChainId,
+  fromToken: o.input,
+  toChain: o.outputChainId,
+  toToken: o.output,
+  fromAmount: o.amountWei.toString(),
+  disablePermit: 1,
+});
+
+export async function getQuote(o: ISwapperParams): Promise<IQuote|undefined> {
+  if (!routerByChainId[o.inputChainId]) return undefined;
+  // NOTE: Required for validateQuoteParams
+  o.payer = o.payer || o.testPayer!;
+  if (!validateQuoteParams(o)) throw new Error("invalid input");
+  const params = convertParams(o);
+  try {
+    const url = `${apiRoot}quote?${qs.stringify(params)}`;
+    const res = await fetch(url);
+    if (res.status >= 400)
+      throw new Error(`${res.status}: ${res.statusText} - ${await res.text?.()}`);
+    return await res.json();
+  } catch (e) {
+    console.error(`getQuote failed: ${e}`);
+  }
+}
+
+// NOTE: Expects referrer to be an EVM address
+export async function getTransactionRequest(o: ISwapperParams): Promise<ITransactionRequestWithEstimate|undefined> {
+  const quote = await getQuote(o);
+  if (!quote) return undefined;
+  const params = {
+    quote,
+    toAddress: o.receiver ?? o.payer ?? o.testPayer,
+    fromAddress: o.payer ?? o.testPayer,
+    partner: o.referrer
+  };
+  try {
+    const res = await fetch(
+      `${apiRoot}swap`,
+      {
+        method: "POST",
+        headers: { "Content-Type": "application/json" },
+        body: JSON.stringify(params),
+      },
+    );
+    if (res.status >= 400)
+      throw new Error(`${res.status}: ${res.statusText} - ${await res.text?.()}`);
+    const swap = await res.json();
+    return {
+      ...swap.tx,
+      estimatedGas: swap.tx.gasLimit,
+    };
+  } catch (e) {
+    console.error(`getTransactionRequest failed: ${e}`);
+  }
+}
diff --git a/src/index.ts b/src/index.ts
index a01af80..6b5afd5 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -7,6 +7,7 @@ import * as KyberSwap from "./KyberSwap";
 import * as Squid from "./Squid";
 import * as LiFi from "./LiFi";
 import * as Socket from "./Socket";
+import * as Sifi from "./Sifi";
 
 import { Aggregator, AggregatorId, ISwapperParams, ITransactionRequestWithEstimate } from "./types";
 
@@ -19,6 +20,7 @@ export const aggregatorById: { [key: string]: Aggregator } = {
   [AggregatorId.SQUID]: <Aggregator>Squid,
   [AggregatorId.LIFI]: <Aggregator>LiFi,
   [AggregatorId.SOCKET]: <Aggregator>Socket,
+  [AggregatorId.SIFI]: <Aggregator>Sifi,
 };
 
 /**
@@ -125,5 +127,6 @@ export {
   KyberSwap,
   Squid,
   LiFi,
-  Socket
+  Socket,
+  Sifi
 }
diff --git a/src/types.ts b/src/types.ts
index 936ba91..86dc27b 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -10,6 +10,7 @@ export enum AggregatorId {
   ONE_INCH = "ONE_INCH",
   ZERO_X = "ZERO_X",
   PARASWAP = "PARASWAP",
+  SIFI = "SIFI",
 }
 
 export interface ISwapperParams {
diff --git a/test/unit/swapper.client.test.ts b/test/unit/swapper.client.test.ts
index 998113c..a1fb0dc 100644
--- a/test/unit/swapper.client.test.ts
+++ b/test/unit/swapper.client.test.ts
@@ -36,6 +36,10 @@ describe("swapper.client.test", function () {
       for (const tr of (await getTransactionRequestByAggregatorCases(AggregatorId.ZERO_X)))
         expect(tr?.data).to.be.a("string");
     });
+    it("Sifi", async function () {
+      for (const tr of (await getTransactionRequestByAggregatorCases(AggregatorId.SIFI)))
+        expect(tr?.data).to.be.a("string");
+    });
   })
 });
 
diff --git a/test/utils/cases.ts b/test/utils/cases.ts
index a44ba2e..8d7fbed 100644
--- a/test/utils/cases.ts
+++ b/test/utils/cases.ts
@@ -74,6 +74,15 @@ export const cases = (): ISwapperParams[] => {
           testPayer: addresses[250].accounts!.impersonate,
           payer: "",
         },
+        {
+          aggregatorId,
+          inputChainId: 42161, // Arbitrum One
+          input: addresses[42161].tokens.DAI,
+          output: addresses[42161].tokens.USDCE,
+          amountWei: 100 * 1e18, // string to prevent overflow
+          testPayer: addresses[42161].accounts!.impersonate,
+          payer: "",
+        },
       ],
     );
   }