diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..edd9109
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,5 @@
+export interface Params {
+    [key: string]: string | number;
+}
+
+export default function interpolate(str: string, params: Params): string;
diff --git a/package.json b/package.json
index d84586c..6cbf5e9 100644
--- a/package.json
+++ b/package.json
@@ -39,5 +39,6 @@
   },
   "engines": {
     "node": ">=8"
-  }
+  },
+  "types": "./index.d.ts"
 }