diff --git a/build.config.js b/build.config.js
index 6ad5e9d..210e364 100644
--- a/build.config.js
+++ b/build.config.js
@@ -1,6 +1,7 @@
 export default {
-    entries: ["./index.js"],
-    rollup: {
-        emitCJS: true,
-    },
-};
\ No newline at end of file
+  entries: ['./index.js'],
+  rollup: {
+    emitCJS: true,
+  },
+  failOnWarn: false,
+};
diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..890c396
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,56 @@
+/// <reference types="node" />
+
+/**
+ * These definitions were written by BendingBender (https://github.com/BendingBender)
+ */
+
+export = crc32;
+
+/**
+ * crc32 that works with binary data and fancy character sets.
+ *
+ * @example
+ * import crc32 = require('buffer-crc32');
+ *
+ * // works with buffers
+ * const buf = Buffer.from([0x00, 0x73, 0x75, 0x70, 0x20, 0x62, 0x72, 0x6f, 0x00]);
+ * crc32(buf); // -> <Buffer 94 5a ab 4a>
+ *
+ * // will cast to buffer if given a string, so you can
+ * // directly use foreign characters safely
+ * crc32('自動販売機'); // -> <Buffer cb 03 1a c5>
+ *
+ * // and works in append mode too
+ * let partialCrc = crc32('hey');
+ * partialCrc = crc32(' ', partialCrc);
+ * partialCrc = crc32('sup', partialCrc);
+ * partialCrc = crc32(' ', partialCrc);
+ * const finalCrc = crc32('bros', partialCrc); // -> <Buffer 47 fa 55 70>
+ */
+declare function crc32(input: string | Buffer, partialCrc?: Buffer | number): Buffer;
+
+declare namespace crc32 {
+  /**
+   * Convenience method that returns a signed int instead of a `Buffer`.
+   *
+   * @example
+   * import crc32 = require('buffer-crc32');
+   *
+   * // works with buffers
+   * const buf = Buffer.from([0x00, 0x73, 0x75, 0x70, 0x20, 0x62, 0x72, 0x6f, 0x00]);
+   * crc32.signed(buf); // -> -1805997238
+   */
+  function signed(buffer: string | Buffer, partialCrc?: Buffer | number): number;
+
+  /**
+   * Convenience method that returns an unsigned int instead of a `Buffer`.
+   *
+   * @example
+   * import crc32 = require('buffer-crc32');
+   *
+   * // works with buffers
+   * const buf = Buffer.from([0x00, 0x73, 0x75, 0x70, 0x20, 0x62, 0x72, 0x6f, 0x00]);
+   * crc32.unsigned(buf); // -> 2488970058
+   */
+  function unsigned(buffer: string | Buffer, partialCrc?: Buffer | number): number;
+}
diff --git a/package.json b/package.json
index 5023474..4ee918e 100644
--- a/package.json
+++ b/package.json
@@ -2,7 +2,7 @@
   "author": "Brian J. Brennan <brianloveswords@gmail.com>",
   "name": "buffer-crc32",
   "description": "A pure javascript CRC32 algorithm that plays nice with binary data",
-  "version": "0.2.13",
+  "version": "1.0.0-RC9",
   "licenses": [
     {
       "type": "MIT",
@@ -22,7 +22,7 @@
   },
   "scripts": {
     "test": "tap tests/*.test.js --reporter classic",
-    "build": "npx unbuild@2.0.0",
+    "build": "npx unbuild@2.0.0 && npx cpy-cli index.d.ts dist --rename=index.d.cts && npx cpy-cli index.d.ts dist --rename=index.d.mts",
     "prepublishOnly": "npm run build",
     "format": "prettier --write --log-level warn \"**/*.{json,md,js}\""
   },
@@ -36,6 +36,7 @@
     "node": ">=8.0.0"
   },
   "license": "MIT",
+  "type": "commonjs",
   "exports": {
     ".": {
       "import": "./dist/index.mjs",
@@ -43,7 +44,11 @@
     }
   },
   "main": "./dist/index.cjs",
+  "types": "./index.d.ts",
   "files": [
-    "dist"
+    "dist",
+    "index.d.ts",
+    "LICENSE",
+    "README.md"
   ]
 }