diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..6bcc928
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,11 @@
+/**
+ * Returns the SHA-256 hash of `message` as an hexadecimal string.
+ * @param message The message to hash
+ */
+export function sha256(message: string | ArrayLike<number> | Uint8Array | ArrayBuffer): string;
+
+/**
+ * Returns the SHA-224 hash of `message` as an hexadecimal string.
+ * @param message The message to hash
+ */
+export function sha224(message: string | ArrayLike<number> | Uint8Array | ArrayBuffer): string;