diff --git a/index.js b/index.js
index d1a6467..c4ebcdc 100644
--- a/index.js
+++ b/index.js
@@ -20,7 +20,7 @@ function storeResults(images, subreddit) {
     return getRandomImage;
 }
 
-module.exports = function (subreddit) {
+function randomPuppy(subreddit) {
     subreddit = (typeof subreddit === 'string' && subreddit.length !== 0) ? subreddit : 'puppies';
 
     if (randomCache[subreddit]) {
@@ -30,4 +30,22 @@ module.exports = function (subreddit) {
     return got(`https://imgur.com/r/${subreddit}/hot.json`, {json: true})
         .then(response => storeResults(response.body.data, subreddit))
         .then(getRandomImage => formatResult(getRandomImage));
+}
+
+function callback(subreddit, cb) {
+    randomPuppy(subreddit)
+        .then(url => cb(null, url))
+        .catch(err => cb(err));
+}
+
+// subreddit is optional
+// callback support is provided for a training exercise
+module.exports = (subreddit, cb) => {
+    if (typeof cb === 'function') {
+        callback(subreddit, cb);
+    } else if (typeof subreddit === 'function') {
+        callback(null, subreddit);
+    } else {
+        return randomPuppy(subreddit);
+    }
 };
diff --git a/package.json b/package.json
index ac1cf6e..eeacb79 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "random-puppy",
-  "version": "1.0.0",
+  "version": "1.0.1",
   "description": "Get a random puppy image url.",
   "license": "MIT",
   "repository": "dylang/random-puppy",
@@ -19,7 +19,12 @@
     "index.js"
   ],
   "keywords": [
-    "puppy", "doggie", "dog", "imgur", "random", "placeholder"
+    "puppy",
+    "doggie",
+    "dog",
+    "imgur",
+    "random",
+    "placeholder"
   ],
   "dependencies": {
     "got": "^6.3.0",
diff --git a/test.js b/test.js
index f3c1a90..63ea031 100644
--- a/test.js
+++ b/test.js
@@ -8,6 +8,24 @@ test('get random', async t => {
     t.regex(result, imgurRegEx);
 });
 
+test.cb('use callback', t => {
+    t.plan(2);
+    randomPuppy((err, result) => {
+        t.falsy(err);
+        t.regex(result, imgurRegEx);
+        t.end();
+    });
+});
+
+test.cb('use callback and different subreddit', t => {
+    t.plan(2);
+    randomPuppy('aww', (err, result) => {
+        t.falsy(err);
+        t.regex(result, imgurRegEx);
+        t.end();
+    });
+});
+
 test('get more random', async t => {
     const result1 = await randomPuppy();
     t.regex(result1, imgurRegEx);