diff --git a/package.json b/package.json
index d6edd2e..19dff12 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,13 @@
   ],
   "license": "MIT",
   "main": "dist/index.js",
+  "exports": {
+    ".": {
+      "require": "./dist/index.js",
+      "types": "./dist/index.d.ts"
+    },
+    "./package.json": "./package.json"
+  },
   "peerDependencies": {
     "@types/nodemailer": "^6.4.9",
     "nodemailer": "^6.9.4"
diff --git a/src/lib/transport.ts b/src/lib/transport.ts
index bfe64de..f9ac4bf 100644
--- a/src/lib/transport.ts
+++ b/src/lib/transport.ts
@@ -1,5 +1,4 @@
 import { Transport } from "nodemailer";
-import MailMessage from "nodemailer/lib/mailer/mail-message";
 
 import MailtrapClient from "./MailtrapClient";
 import normalizeCallback from "./normalizer";
@@ -11,6 +10,7 @@ import {
   MailtrapResponse,
   MailtrapTransporter,
   NormalizeCallback,
+  MailMessage,
 } from "../types/transport";
 
 const { TRANSPORT_SETTINGS } = CONFIG;
diff --git a/src/types/transport.ts b/src/types/transport.ts
index 5c83062..0522c23 100644
--- a/src/types/transport.ts
+++ b/src/types/transport.ts
@@ -1,6 +1,6 @@
 import NodemailerMail = require("nodemailer/lib/mailer");
 
-import { Transporter } from "nodemailer";
+import { Transport, Transporter } from "nodemailer";
 import {
   SendResponse,
   SendError,
@@ -51,3 +51,5 @@ export interface MailtrapTransporter extends Transporter<MailtrapResponse> {
     mailOptions: MailtrapMailOptions | MailtrapMailOptionsSandbox
   ): Promise<MailtrapResponse>;
 }
+
+export type MailMessage<T> = Parameters<Transport<T>["send"]>[0];
diff --git a/tsconfig.json b/tsconfig.json
index 3f5ecf7..ef6d79f 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,7 +7,10 @@
     "declaration": true,
     "outDir": "./dist",
     "skipLibCheck": true,
-    "esModuleInterop": true
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "declarationMap": true,
+    "forceConsistentCasingInFileNames": true
   },
   "include": ["src"],
   "exclude": ["node_modules", "examples"]