diff --git a/src/searchly/api/v1/controllers/similarity.py b/src/searchly/api/v1/controllers/similarity.py
index 86ba484..096d3b2 100644
--- a/src/searchly/api/v1/controllers/similarity.py
+++ b/src/searchly/api/v1/controllers/similarity.py
@@ -1,7 +1,7 @@
 from flask import request
 
 from src.searchly.api.v1.services import response
-from src.searchly.helper import searcher, log
+from src.searchly.helper import searcher, log, cache
 
 
 def by_song():
@@ -10,14 +10,24 @@ def by_song():
     :return: JSON response.
     """
     try:
+        # Parameters retrieving
         song_id = request.args.get('song_id')
         if not song_id:
             return response.make(error=True, message='`song_id` missed as a query parameter.')
+        # Cache processing
+        method = by_song.__name__
+        key = '{}'.format(song_id)
+        results_cached = cache.get(method, key)
+        if results_cached is not None:
+            return response.make(response=results_cached, cached=True)
+        # Feature extraction
         features = searcher.extract_features_from_song(song_id)
         if features is None:
-            return response.make(error=True, message='Song not found.')
+            return response.make(error=True, message='Song not found.', method=method, key=key)
+        # Searching
         results = searcher.search(features, song_id=song_id)
-        return response.make(error=False, response=dict(similarity_list=results))
+        # Return results and refresh cache
+        return response.make(error=False, response=dict(similarity_list=results), method=method, key=key)
     except Exception as e:
         log.error(f'Unexpected error: [{e}]')
         log.exception(e)
@@ -30,6 +40,7 @@ def by_content():
     :return: JSON response.
     """
     try:
+        # Parameters retrieving
         request_json = request.json
         content = response.get('content', request_json)
         if not content:
diff --git a/src/searchly/api/v1/services/response.py b/src/searchly/api/v1/services/response.py
index 9c84c06..cc373c1 100644
--- a/src/searchly/api/v1/services/response.py
+++ b/src/searchly/api/v1/services/response.py
@@ -1,19 +1,37 @@
-def make(error, message=None, response=None, code=200):
+from flask import jsonify
+
+from src.searchly.helper import cache
+
+
+def make(error=None, message=None, response=None, code=200, cached=False, method=None, key=None):
     """
     API response generator function.
     :param error: True if the response has to be flagged as an error, False otherwise.
     :param message: Error message string formatted. Only being used when [error == True]
     :param response: JSON response dictionary formatted. Only being used when [error == False]
     :param code: Response code.
+    :param cached: True if the response is from the cache, False otherwise.
+    :param method: Cache method.
+    :param key: Cache key.
     :return: JSON response.
     """
-    response_dict = dict(error=error)
-    if error:
-        assert type(message) is str
-        response_dict['message'] = message
-    else:
+    if cached:
         assert type(response) is dict
-        response_dict['response'] = response
+        response_dict = jsonify(response)
+        response_dict.headers['X-Cache'] = 'HIT'
+    else:
+        assert error is not None
+        response_dict = dict(error=error)
+        if error:
+            assert type(message) is str
+            response_dict['message'] = message
+        else:
+            assert type(response) is dict
+            response_dict['response'] = response
+        if method is not None and key is not None:
+            cache.refresh(method, key, response_dict)
+        response_dict = jsonify(response_dict)
+        response_dict.headers['X-Cache'] = 'MISS'
     return response_dict, code