diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..9133c32
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,34 @@
+
+declare module 'amazon-user-pool-srp-client' {
+  export interface SRPClient {
+    poolName: string
+    N: string
+    k: string
+    g: string
+    infoBits: string
+    constructor(poolName: string)
+    generateRandomSmallA(): string 
+    calculateA(a: string): string 
+    calculateU(A: string, B: string): string
+    getPasswordAuthenticationKey(
+      username: string,
+      password: string,
+      serverBValue: string,
+      salt: string
+    ): string
+    padHex(bigInt: string): string
+    hash(str: string): string
+    hexHash(str: string): string
+    computehkdf(ikm: string, salt: string): string
+  }
+
+  export function calculateSignature (
+    hkdf: string,
+    userPoolId: string,
+    username: string,
+    secretBlock: string,
+    dateNow: string
+  ): string 
+
+  export function getNowString(): string
+}