diff --git a/follower_bot.py b/follower_bot.py
index df7070ce..bb700353 100644
--- a/follower_bot.py
+++ b/follower_bot.py
@@ -1,51 +1,93 @@
 import os
-import json
 import requests
 from requests.auth import HTTPBasicAuth
 
 
-print('Hi! I am GitHub follower bot.')
-print('Letting you follow your all followers!')
-print('Stating fetching your follower lists...\n')
-
-github_user = os.getenv('github_user')
-personal_github_token = os.getenv('personal_github_token')
-
-follower_url = 'https://api.github.com/users/%s/followers?page=' % (github_user)
-update_followed_user = 'https://api.github.com/user/following/%s'
-page = 1
-follower_counter = 0
-
-file_handler = open('./followers.txt', 'r')
-follower_txt_lists = ''.join(file_handler.readlines()).split('\n')[0:-1]
-file_handler.close()
-
-file_handler = open('./followers.txt', 'a')
-
-while True:
-    response = requests.get(follower_url + str(page))
-    follower_lists = json.loads(response.text)
-    follower_lists_len = len(follower_lists)
-    if follower_lists_len == 0:
-        break
-    follower_counter += follower_lists_len
-    for follower_info in follower_lists:
-        headers = { 'user-agent': 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36' }
-        user = follower_info['login']
-        if user in follower_txt_lists:
-            continue
-        response = requests.put(update_followed_user % (user), auth=HTTPBasicAuth(github_user, personal_github_token), headers=headers)
-        if response.status_code == 204:
-            print('User: %s has been followed!' % user)
-            file_handler.write(user + '\n')
-        else:
-            print(response.text)
-    page += 1
-
-file_handler.close()
-
-file_handler = open('follower_counter.txt', 'w')
-file_handler.write(str(follower_counter) + '\n')
-file_handler.close()
-
-print('\nFollowing users from your followed lists are done!')
+def fetch_followers(github_user, page):
+    """Fetch a list of followers for a given GitHub user and page."""
+    url = f"https://api.github.com/users/{github_user}/followers?page={page}"
+    response = requests.get(url)
+    response.raise_for_status()
+    return response.json()
+
+
+def follow_user(github_user, personal_token, user_to_follow):
+    """Send a follow request to a specific user."""
+    url = f"https://api.github.com/user/following/{user_to_follow}"
+    headers = {
+        "User-Agent": (
+            "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
+            "(KHTML, like Gecko) Chrome/93.0.4577.63 Safari/537.36"
+        )
+    }
+    response = requests.put(
+        url, auth=HTTPBasicAuth(github_user, personal_token), headers=headers
+    )
+    return response.status_code
+
+
+def load_existing_followers(file_path):
+    """Load the list of already followed users from a file."""
+    if not os.path.exists(file_path):
+        return set()
+    with open(file_path, "r") as file:
+        return set(file.read().strip().splitlines())
+
+
+def save_new_follower(file_path, username):
+    """Append a newly followed user to the file."""
+    with open(file_path, "a") as file:
+        file.write(f"{username}\n")
+
+
+def save_follower_count(file_path, count):
+    """Save the total number of followers fetched."""
+    with open(file_path, "w") as file:
+        file.write(f"{count}\n")
+
+
+def main():
+    print("Hi! I am GitHub follower bot.")
+    print("Letting you follow your all followers!")
+    print("Starting to fetch your follower list...\n")
+
+    github_user = os.getenv("github_user")
+    personal_github_token = os.getenv("personal_github_token")
+
+    if not github_user or not personal_github_token:
+        print("Error: Please set the 'github_user' and 'personal_github_token' environment variables.")
+        return
+
+    followers_file = "./followers.txt"
+    follower_counter_file = "./follower_counter.txt"
+
+    existing_followers = load_existing_followers(followers_file)
+    follower_counter = 0
+    page = 1
+
+    while True:
+        followers = fetch_followers(github_user, page)
+        if not followers:
+            break
+
+        follower_counter += len(followers)
+        for follower in followers:
+            username = follower["login"]
+            if username in existing_followers:
+                continue
+
+            status_code = follow_user(github_user, personal_github_token, username)
+            if status_code == 204:
+                print(f"User: {username} has been followed!")
+                save_new_follower(followers_file, username)
+            else:
+                print(f"Failed to follow {username}. Status code: {status_code}")
+
+        page += 1
+
+    save_follower_count(follower_counter_file, follower_counter)
+    print("\nFollowing users from your follower list is done!")
+
+
+if __name__ == "__main__":
+    main()