diff --git a/packages/providers/src.ts/url-json-rpc-provider.ts b/packages/providers/src.ts/url-json-rpc-provider.ts
index 83272cbf..6c20f0c4 100644
--- a/packages/providers/src.ts/url-json-rpc-provider.ts
+++ b/packages/providers/src.ts/url-json-rpc-provider.ts
@@ -13,7 +13,7 @@ import { JsonRpcProvider, JsonRpcSigner } from "./json-rpc-provider";
 type getUrlFunc = (network: Network, apiKey: string) => string | ConnectionInfo;
 
 export abstract class UrlJsonRpcProvider extends JsonRpcProvider {
-    readonly apiKey: string;
+    readonly apiKey: any;
 
     constructor(network?: Networkish, apiKey?: any) {
         logger.checkAbstract(new.target, UrlJsonRpcProvider);