diff --git a/packages/api/src/api/contract/contract.controller.spec.ts b/packages/api/src/api/contract/contract.controller.spec.ts
index f2dae4cc0..9b5dbe7f8 100644
--- a/packages/api/src/api/contract/contract.controller.spec.ts
+++ b/packages/api/src/api/contract/contract.controller.spec.ts
@@ -442,7 +442,7 @@ describe("ContractController", () => {
         codeFormat: "vyper-multi-file",
         compilerVyperVersion: "0.3.3",
         compilerZkvyperVersion: "v1.3.11",
-        constructorArguments: null,
+        constructorArguments: "0x",
         contractAddress: "0x14174c76E073f8efEf5C1FE0dd0f8c2Ca9F21e62",
         contractName: "contracts/Greeter.vy:Greeter",
         optimizationUsed: true,
diff --git a/packages/api/src/api/contract/contract.controller.ts b/packages/api/src/api/contract/contract.controller.ts
index 8381e6a18..91283cf3a 100644
--- a/packages/api/src/api/contract/contract.controller.ts
+++ b/packages/api/src/api/contract/contract.controller.ts
@@ -195,7 +195,7 @@ export class ContractController {
             ? request.constructorArguements.slice(0, 2) !== "0x"
               ? `0x${request.constructorArguements}`
               : request.constructorArguements
-            : null,
+            : "0x",
           ...(isSolidityContract && {
             compilerZksolcVersion: request.zksolcVersion,
             compilerSolcVersion: request.compilerversion,