--- a
+++ b/ddpg/replay_buffer.py
@@ -0,0 +1,34 @@
+from collections import deque
+import random
+
+class ReplayBuffer(object):
+
+    def __init__(self, buffer_size):
+        self.buffer_size = buffer_size
+        self.num_experiences = 0
+        self.buffer = deque()
+
+    def get_batch(self, batch_size):
+        # Randomly sample batch_size examples
+        return random.sample(self.buffer, batch_size)
+
+    def size(self):
+        return self.buffer_size
+
+    def add(self, state, action, reward, new_state, done):
+        experience = (state, action, reward, new_state, done)
+        if self.num_experiences < self.buffer_size:
+            self.buffer.append(experience)
+            self.num_experiences += 1
+        else:
+            self.buffer.popleft()
+            self.buffer.append(experience)
+
+    def count(self):
+        # if buffer is full, return buffer size
+        # otherwise, return experience counter
+        return self.num_experiences
+
+    def erase(self):
+        self.buffer = deque()
+        self.num_experiences = 0
\ No newline at end of file