diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..15f3d15
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,9 @@
+export = Rainbow;
+declare function Rainbow(): void;
+declare class Rainbow {
+    setSpectrum: (...args: string[]) => Rainbow;
+    setSpectrumByArray: (array: string[]) => Rainbow;
+    colourAt: (number: number) => string;
+    colorAt: (number: number) => string;
+    setNumberRange: (minNumber: number, maxNumber: number) => Rainbow;
+}