diff --git a/packages/sdk/src/Sygma.ts b/packages/sdk/src/Sygma.ts
index d7691a41f..f8f70fc64 100644
--- a/packages/sdk/src/Sygma.ts
+++ b/packages/sdk/src/Sygma.ts
@@ -620,7 +620,7 @@ export class Sygma implements SygmaSDK {
         fromDomainID,
         toDomainID,
         resourceID,
-        tokenAmount: Number(amount),
+        tokenAmount: amount,
         recipientAddress,
       });
 
@@ -665,7 +665,7 @@ export class Sygma implements SygmaSDK {
       fromDomainID: parseInt(this.bridgeSetup!.chain1.domainId),
       toDomainID: parseInt(this.bridgeSetup!.chain2.domainId),
       resourceID,
-      tokenAmount: Number(amount),
+      tokenAmount: amount,
       feeOracleBaseUrl,
       feeOracleHandlerAddress,
       overridedResourceId, // '0xbA2aE424d960c26247Dd6c32edC70B295c744C43',
diff --git a/packages/sdk/src/fee/__test__/basicFee.test.ts b/packages/sdk/src/fee/__test__/basicFee.test.ts
index e5dd1e67d..35292e42a 100644
--- a/packages/sdk/src/fee/__test__/basicFee.test.ts
+++ b/packages/sdk/src/fee/__test__/basicFee.test.ts
@@ -27,7 +27,7 @@ describe('CalculateBasicFee', () => {
       fromDomainID: '1',
       toDomainID: '2',
       resourceID: '0x0000000000000000000000000000000000000000000000000000000000000000',
-      tokenAmount: 100,
+      tokenAmount: "0.001",
       recipientAddress: '0xF4314cb9046bECe6AA54bb9533155434d0c76909',
     });
 
@@ -54,7 +54,7 @@ describe('CalculateBasicFee', () => {
         fromDomainID: '1',
         toDomainID: '2',
         resourceID: '0x0000000000000000000000000000000000000000000000000000000000000000',
-        tokenAmount: 100,
+        tokenAmount: "100",
         recipientAddress: '0xF4314cb9046bECe6AA54bb9533155434d0c76909',
       });
     } catch (e) {
diff --git a/packages/sdk/src/fee/__test__/feeOracle.test.ts b/packages/sdk/src/fee/__test__/feeOracle.test.ts
index 451bb3aa9..ca178f1b7 100644
--- a/packages/sdk/src/fee/__test__/feeOracle.test.ts
+++ b/packages/sdk/src/fee/__test__/feeOracle.test.ts
@@ -71,16 +71,33 @@ describe('feeOracle', () => {
           });
         } catch (e) {
           // @ts-ignore
-          expect(e.message).toMatch('Invalid fee oracle response');
+          expect(e.message).toMatch('Internal Error');
         }
       });
+
+      it('return error message from fee oracle server', async () => {
+        (fetch as jest.MockedFunction<typeof fetch>).mockResolvedValue(
+          new Response(JSON.stringify({error: 'sick'}), {
+            url: 'url',
+            status: 200,
+            statusText: 'OK'
+          }),
+        );
+        await expect(
+          requestFeeFromFeeOracle({
+            feeOracleBaseUrl: 'http://localhost:8091',
+            fromDomainID: 1,
+            toDomainID: 2,
+            resourceID: '0x0000000000000000000000000000000000000000000000000000000000000001',
+          })).rejects.toThrowError("sick");
+      });
     });
 
     describe('createOracleFeeData', () => {
       it('builds feeData', () => {
         const feeData = createOracleFeeData(
           oracleResponse.response,
-          10,
+          "10",
           '0x0000000000000000000000000000000000000000000000000000000000000001',
           '0x6937d1d0b52f2fa7f4e071c7e64934ad988a8f21c6bf4f323fc19af4c77e3c5e',
         );
@@ -104,7 +121,7 @@ describe('feeOracle', () => {
           fromDomainID: 1,
           toDomainID: 2,
           resourceID: '0x0000000000000000000000000000000000000000000000000000000000000001',
-          tokenAmount: 100,
+          tokenAmount: "100",
           feeOracleBaseUrl: 'http://localhost:8091',
           feeOracleHandlerAddress: '0xa9ddD97e1762920679f3C20ec779D79a81903c0B',
           overridedResourceId: '0xbA2aE424d960c26247Dd6c32edC70B295c744C43',
@@ -118,6 +135,32 @@ describe('feeOracle', () => {
         });
       });
 
+      it('get the fee data with no oracle key', async () => {
+        (fetch as jest.MockedFunction<typeof fetch>).mockResolvedValue(
+          new Response(JSON.stringify(oracleResponse), { url: 'url', status: 200, statusText: 'OK' }),
+        );
+
+        const provider = new ethers.providers.JsonRpcProvider();
+        const feeData = await calculateFeeData({
+          provider,
+          sender: ethers.constants.AddressZero,
+          recipientAddress: '0x74d2946319bEEe4A140068eb83F9ee3a90B06F4f',
+          fromDomainID: 1,
+          toDomainID: 2,
+          resourceID: '0x0000000000000000000000000000000000000000000000000000000000000001',
+          tokenAmount: "100",
+          feeOracleBaseUrl: 'http://localhost:8091',
+          feeOracleHandlerAddress: '0xa9ddD97e1762920679f3C20ec779D79a81903c0B',
+        });
+        expect(feeData?.feeData).toContain(oracleResponse.response.signature)
+        expect(feeData).toMatchObject({
+          calculatedRate: '0.00000000000000001',
+          erc20TokenAddress: '0x141F8690A87A7E57C2E270ee77Be94935970c035',
+          feeData:
+            '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',
+        });
+      });
+
       it('get error', async () => {
         (fetch as jest.MockedFunction<typeof fetch>).mockRejectedValue('Err');
         try {
@@ -129,7 +172,7 @@ describe('feeOracle', () => {
             fromDomainID: 1,
             toDomainID: 2,
             resourceID: '0x0000000000000000000000000000000000000000000000000000000000000001',
-            tokenAmount: 100,
+            tokenAmount: "100",
             feeOracleBaseUrl: 'http://localhost:8091',
             feeOracleHandlerAddress: '0xa9ddD97e1762920679f3C20ec779D79a81903c0B',
             overridedResourceId: '0xbA2aE424d960c26247Dd6c32edC70B295c744C43',
diff --git a/packages/sdk/src/fee/basicFee.ts b/packages/sdk/src/fee/basicFee.ts
index 73951f499..2872707a4 100644
--- a/packages/sdk/src/fee/basicFee.ts
+++ b/packages/sdk/src/fee/basicFee.ts
@@ -1,5 +1,5 @@
 import { BasicFeeHandler__factory as BasicFeeHandler } from '@buildwithsygma/sygma-contracts';
-import { ethers } from 'ethers';
+import { ethers, utils } from 'ethers';
 import { FeeDataResult } from '../types';
 import { createERCDepositData } from '../utils/helpers';
 
@@ -25,10 +25,11 @@ export const calculateBasicfee = async ({
   fromDomainID: string;
   toDomainID: string;
   resourceID: string;
-  tokenAmount: number;
+  tokenAmount: string;
   recipientAddress: string;
 }): Promise<FeeDataResult | Error> => {
-  const depositData = createERCDepositData(tokenAmount, 20, recipientAddress);
+  const convertedAmount = utils.parseUnits(tokenAmount, 18);
+  const depositData = createERCDepositData(convertedAmount, 20, recipientAddress);
   // WHY 0X00 AND NOT 0X0?
   const feeData = '0x00';
   const BasicFeeHandlerInstance = BasicFeeHandler.connect(basicFeeHandlerAddress, provider);
diff --git a/packages/sdk/src/fee/feeOracle.ts b/packages/sdk/src/fee/feeOracle.ts
index 9f6ba9565..fc50f8c09 100644
--- a/packages/sdk/src/fee/feeOracle.ts
+++ b/packages/sdk/src/fee/feeOracle.ts
@@ -1,5 +1,5 @@
 import { FeeHandlerWithOracle__factory } from '@buildwithsygma/sygma-contracts';
-import { ethers } from 'ethers';
+import { ethers, utils } from 'ethers';
 import fetch from 'node-fetch';
 import EthCrypto from 'eth-crypto';
 
@@ -22,7 +22,7 @@ type OracleResponse = {
  */
 export const createOracleFeeData = (
   oracleResponse: OracleResource,
-  amount: number,
+  amount: string,
   tokenResource: string,
   oraclePrivateKey?: string,
 ): string => {
@@ -70,7 +70,7 @@ export const createOracleFeeData = (
     return oracleMessage + signature.substring(2) + toHex(amount, 32).substring(2);
   } else {
     signature = oracleResponse.signature;
-    return oracleMessage + signature + toHex(0, 32).substring(2);
+    return oracleMessage + signature + toHex(amount, 32).substring(2);
   }
 };
 
@@ -99,13 +99,13 @@ export const calculateFeeData = async ({
   fromDomainID: number;
   toDomainID: number;
   resourceID: string;
-  tokenAmount: number;
+  tokenAmount: string;
   feeOracleBaseUrl: string;
   feeOracleHandlerAddress: string;
   overridedResourceId?: string;
   oraclePrivateKey?: string;
 }): Promise<FeeDataResult | undefined> => {
-  const depositData = createERCDepositData(tokenAmount, 20, recipientAddress);
+  const depositData = createERCDepositData(utils.parseUnits(tokenAmount, 18), 20, recipientAddress);
   let oracleResponse;
   try {
     oracleResponse = await requestFeeFromFeeOracle({
@@ -185,6 +185,6 @@ export const requestFeeFromFeeOracle = async ({
       return data.response;
     }
   } catch (e) {
-    return Promise.reject(new Error('Invalid fee oracle response'));
+    return Promise.reject(e);
   }
 };
diff --git a/packages/sdk/src/utils/helpers.ts b/packages/sdk/src/utils/helpers.ts
index a7a96dc98..01c44d0fd 100644
--- a/packages/sdk/src/utils/helpers.ts
+++ b/packages/sdk/src/utils/helpers.ts
@@ -8,7 +8,8 @@ import { utils, BigNumber } from 'ethers';
  * @returns {string}
  */
 export const toHex = (covertThis: string | number | BigNumber, padding: number): string => {
-  return utils.hexZeroPad(utils.hexlify(BigNumber.from(covertThis)), padding);
+  const amount = covertThis instanceof BigNumber ? covertThis : BigNumber.from(covertThis);
+  return utils.hexZeroPad(utils.hexlify(amount), padding);
 };
 
 /**