diff --git a/README.md b/README.md
index 8cb3a38..2b681f9 100644
--- a/README.md
+++ b/README.md
@@ -558,6 +558,8 @@ Create a base58check encoder/decoder with custom hash functions
 
 ### `@exodus/bytes/wif.js`
 
+Wallet Import Format (WIF) encoding and decoding.
+
 ```js
 import { fromWifString, toWifString } from '@exodus/bytes/wif.js'
 import { fromWifStringSync, toWifStringSync } from '@exodus/bytes/wif.js'
@@ -565,11 +567,34 @@ import { fromWifStringSync, toWifStringSync } from '@exodus/bytes/wif.js'
 
 On non-Node.js, requires peer dependency [@noble/hashes](https://www.npmjs.com/package/@noble/hashes) to be installed.
 
-#### `async fromWifString(string, version)`
-#### `fromWifStringSync(string, version)`
+#### `async fromWifString(string[, version])`
+
+Decode a WIF string to WIF data
+
+Returns a promise that resolves to an object with `{ version, privateKey, compressed }`.
+
+The optional `version` parameter validates the version byte.
+
+Throws if the WIF string is invalid or version doesn't match.
+
+#### `fromWifStringSync(string[, version])`
+
+Decode a WIF string to WIF data (synchronous)
+
+Returns an object with `{ version, privateKey, compressed }`.
+
+The optional `version` parameter validates the version byte.
+
+Throws if the WIF string is invalid or version doesn't match.
+
 #### `async toWifString({ version, privateKey, compressed })`
+
+Encode WIF data to a WIF string
+
 #### `toWifStringSync({ version, privateKey, compressed })`
 
+Encode WIF data to a WIF string (synchronous)
+
 ### `@exodus/bytes/array.js`
 
 TypedArray utils and conversions.
diff --git a/package.json b/package.json
index fd24be9..df39e9f 100644
--- a/package.json
+++ b/package.json
@@ -119,7 +119,8 @@
     "/utf8.js",
     "/utf8.d.ts",
     "/utf8.node.js",
-    "/wif.js"
+    "/wif.js",
+    "/wif.d.ts"
   ],
   "main": "index.js",
   "module": "index.js",
@@ -198,7 +199,10 @@
       "node": "./utf8.node.js",
       "default": "./utf8.js"
     },
-    "./wif.js": "./wif.js"
+    "./wif.js": {
+      "types": "./wif.d.ts",
+      "default": "./wif.js"
+    }
   },
   "react-native": {
     "./encoding-browser.js": "./encoding-browser.native.js"
diff --git a/wif.d.ts b/wif.d.ts
new file mode 100644
index 0000000..6e038a1
--- /dev/null
+++ b/wif.d.ts
@@ -0,0 +1,76 @@
+/**
+ * Wallet Import Format (WIF) encoding and decoding.
+ *
+ * ```js
+ * import { fromWifString, toWifString } from '@exodus/bytes/wif.js'
+ * import { fromWifStringSync, toWifStringSync } from '@exodus/bytes/wif.js'
+ * ```
+ *
+ * On non-Node.js, requires peer dependency [@noble/hashes](https://www.npmjs.com/package/@noble/hashes) to be installed.
+ *
+ * @module @exodus/bytes/wif.js
+ */
+
+/// <reference types="node" />
+
+import type { Uint8ArrayBuffer } from './array.js';
+
+/**
+ * WIF (Wallet Import Format) data structure
+ */
+export interface Wif {
+  /** Network version byte */
+  version: number;
+  /** 32-byte private key */
+  privateKey: Uint8ArrayBuffer;
+  /** Whether the key is compressed */
+  compressed: boolean;
+}
+
+/**
+ * Decode a WIF string to WIF data
+ *
+ * Returns a promise that resolves to an object with `{ version, privateKey, compressed }`.
+ *
+ * The optional `version` parameter validates the version byte.
+ *
+ * Throws if the WIF string is invalid or version doesn't match.
+ *
+ * @param string - The WIF encoded string
+ * @param version - Optional expected version byte to validate against
+ * @returns The decoded WIF data
+ * @throws Error if the WIF string is invalid or version doesn't match
+ */
+export function fromWifString(string: string, version?: number): Promise<Wif>;
+
+/**
+ * Decode a WIF string to WIF data (synchronous)
+ *
+ * Returns an object with `{ version, privateKey, compressed }`.
+ *
+ * The optional `version` parameter validates the version byte.
+ *
+ * Throws if the WIF string is invalid or version doesn't match.
+ *
+ * @param string - The WIF encoded string
+ * @param version - Optional expected version byte to validate against
+ * @returns The decoded WIF data
+ * @throws Error if the WIF string is invalid or version doesn't match
+ */
+export function fromWifStringSync(string: string, version?: number): Wif;
+
+/**
+ * Encode WIF data to a WIF string
+ *
+ * @param wif - The WIF data to encode
+ * @returns The WIF encoded string
+ */
+export function toWifString(wif: Wif): Promise<string>;
+
+/**
+ * Encode WIF data to a WIF string (synchronous)
+ *
+ * @param wif - The WIF data to encode
+ * @returns The WIF encoded string
+ */
+export function toWifStringSync(wif: Wif): string;