diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..72ad1ab
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,27 @@
+type Platform = 'amazon' | 'apple' | 'google' | 'roku';
+
+interface Payment {
+    receipt: any,       // always required
+    productId: string,
+    packageName: string,
+    secret: string,
+    subscription?: boolean,
+    keyObject?: any,    // required, if google
+    userId?: string,    // required, if amazon
+    devToken?: string,  // required, if roku
+}
+
+interface Response {
+    receipt: any,
+    platform: Platform,
+    productId: string,
+    transactionId: string,
+    purchaseDate: number,
+    expirationDate: number,
+}
+
+export function verifyPayment (
+    platform: Platform,
+    payment: Payment,
+    callback: (error: string, response: Response & any) => void
+);