diff --git a/src/lhisp-oauth-client.t.ts b/src/lhisp-oauth-client.t.ts
index cacb4f8..828ec82 100644
--- a/src/lhisp-oauth-client.t.ts
+++ b/src/lhisp-oauth-client.t.ts
@@ -9,7 +9,7 @@ export interface LhispOauthClientConstructorParams {
   apiUrl: string;
   clientId: string;
   clientSecret: string;
-  certificado?: string;
+  certificado?: string | Buffer;
   senhaCertificado?: string;
   authScope?: string;
   authHeaderName?: string;