diff --git a/index.d.ts b/index.d.ts
index 5980eab..9059aa1 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -4,4 +4,22 @@ export interface JwtDecodeOptions {
   header?: boolean;
 }
 
-export default function jwtDecode(token: string, options?: JwtDecodeOptions): unknown;
+export interface JwtHeader {
+  type?: string;
+  alg?: string;
+}
+
+export interface JwtPayload {
+  iss?: string;
+  sub?: string;
+  aud?: string[] | string;
+  exp?: number;
+  nbf?: number;
+  iat?: number;
+  jti?: string;
+}
+
+export default function jwtDecode<T = unknown>(
+  token: string,
+  options?: JwtDecodeOptions
+): T;