diff --git a/backend/forum.py b/backend/forum.py
index e5b39a1..c4c4515 100644
--- a/backend/forum.py
+++ b/backend/forum.py
@@ -6,11 +6,13 @@ app = FastAPI()
 
 class Post:
     id: int
+    thread_id: int
     title: str
     content: str
 
-    def __init__(self, id, title, content):
+    def __init__(self, id, thread_id, title, content):
         self.id = id
+        self.thread_id = thread_id
         self.title = title
         self.content = content
 
@@ -36,25 +38,66 @@ THREADS = []
 
 
 @app.get("/")
-async def home():
-    return POSTS
+async def get_threads():
+    return THREADS
 
 
 @app.post("/post")
 async def create_post(data: PostCreate):
+    id = len(POSTS) + 1
+    title = data.title
+    content = data.content
+
+    # Create thread
+    thread = Thread(
+        id=id,
+        title=title
+    )
+    THREADS.append(thread)
+
+    # Create post
     post = Post(
-        id=len(POSTS) + 1,
-        title=data.title,
-        content=data.content
+        id=id,
+        thread_id=id,
+        title=title,
+        content=content
     )
     POSTS.append(post)
-    return POSTS[-1]
+
+    return post
 
 
-@app.get("/{post_id}")
-async def get_post(post_id: int):
+@app.get("/{thread_id}")
+async def get_thread(thread_id: int):
+    result = []
     for post in POSTS:
-        if post.get('post_id') == post_id:
-            return post
+        if post.thread_id == thread_id:
+            result.append(post)
 
-    return {}
+    return result
+
+
+@app.post("/{thread_id}/post")
+async def create_reply(thread_id: int, data: PostCreate):
+    parent = None
+    for thread in THREADS:
+        if thread.id == thread_id:
+            parent = thread
+
+    if parent:
+        id = len(POSTS) + 1
+        title = data.title
+        content = data.content
+
+        # Create post
+        post = Post(
+            id=id,
+            thread_id=parent.id,
+            title=title,
+            content=content
+        )
+        POSTS.append(post)
+
+        return post
+
+    return {'error': 'could not find parent thread'}