diff --git a/.gitignore b/.gitignore
index 05f5d15..7564f4c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -200,4 +200,8 @@ fabric.properties
 # Android studio 3.1+ serialized cache file
 .idea/caches/build_file_checksums.ser
 
-db/*.sqlite
\ No newline at end of file
+db/*.sqlite
+
+# Ruff
+ruff.toml
+.ruff_cache/
\ No newline at end of file
diff --git a/cogs/birthday.py b/cogs/birthday.py
new file mode 100644
index 0000000..26d3b44
--- /dev/null
+++ b/cogs/birthday.py
@@ -0,0 +1,282 @@
+"""
+Modul for bursdagsfunksjonalitet
+"""
+
+import json
+import os
+from datetime import datetime, time
+from zoneinfo import ZoneInfo
+
+import discord
+from discord.ext import commands, tasks
+
+NORWEGIAN_TIME = ZoneInfo("Europe/Oslo")
+BIRTHDAY_CHECK_TIME = time(hour=8, minute=00, tzinfo=NORWEGIAN_TIME)
+BIRTHDAY_ROLE_TIME = time(hour=0, minute=0, tzinfo=NORWEGIAN_TIME)
+
+
+class Birthday(commands.Cog):
+    """
+    Klasse for bursdagsfunksjonalitet
+    """
+
+    def __init__(self, bot):
+        self.bot = bot
+        self.settings_file = bot.data_dir + "/birthday/innstilinger.json"
+        self.birthdays_file = bot.data_dir + "/birthday/birthdays.json"
+        self.settings = self.load_settings()
+        self.data_cache = self.load_existing_data()
+        self.check_todays_birthday.start()
+        self.remove_birthday_roles.start()
+
+    @discord.app_commands.command(name="bursdag", description="Legg til bursdag")
+    @discord.app_commands.describe(date="Bursdag i format DD.MM")
+    async def add_birthday(self, interaction: discord.Interaction, date: str):
+        """
+        Funksjon som lagrer bursdag
+        """
+        try:
+            day, month = date.split(".")
+            day = int(day)
+            month = int(month)
+
+            if not (1 <= day <= 31 and 1 <= month <= 12):
+                raise ValueError
+
+        except (ValueError, IndexError):
+            return await interaction.response.send_message("Feil format! Bruk `DD.MM`(f.eks. 24.12)", ephemeral=True)
+
+        user = interaction.user
+        today = datetime.now()
+        data = self.load_existing_data()
+        user_id = str(interaction.user.id)
+
+        try:
+            if user_id not in data:
+                data[user_id] = {"username": interaction.user.name, "birthday": date, "updated": today.isoformat()}
+                self.data_cache = data
+                self.save_data(data)
+            else:
+                last_updated_str = data[user_id].get("updated")
+                if last_updated_str:
+                    last_updated = datetime.fromisoformat(last_updated_str)
+                    if (today - last_updated).days < 180:
+                        return await interaction.response.send_message(
+                            "Du kan bare endre bursdagen din hver 6 måned. Prøv igjen senere.", ephemeral=True
+                        )
+                data[user_id] = {"username": interaction.user.name, "birthday": date, "updated": today.isoformat()}
+                self.data_cache = data
+                self.save_data(data)
+
+            await interaction.response.send_message(
+                f"Lagret bursdag for {user.mention}: {date} \nDette blir slettet når serveren forlates."
+            )
+        except Exception as e:
+            self.bot.logger.error(f"Error in add_birthday: {e}")
+            await interaction.response.send_message("En feil oppstod. Prøv igjen senere.", ephemeral=True)
+
+    def load_existing_data(self):
+        data = {}
+        if os.path.exists(self.birthdays_file):
+            with open(self.birthdays_file, "r") as file:
+                data = json.load(file)
+        return data
+
+    def load_settings(self):
+        if os.path.exists(self.settings_file):
+            with open(self.settings_file, "r") as file:
+                return json.load(file)
+        return {}
+
+    def save_settings(self, setting):
+        os.makedirs(os.path.dirname(self.settings_file), exist_ok=True)
+
+        try:
+            with open(self.settings_file, "r") as file:
+                settings = json.load(file)
+        except (FileNotFoundError, json.JSONDecodeError):
+            settings = {}
+
+        settings.update(setting)
+
+        with open(self.settings_file, "w") as file:
+            json.dump(settings, file, indent=4)
+
+    def save_data(self, data):
+        os.makedirs(os.path.dirname(self.birthdays_file), exist_ok=True)
+        with open(self.birthdays_file, "w") as file:
+            json.dump(data, file, indent=4)
+
+    @commands.guild_only()
+    @commands.group(name="bursdag")
+    async def birthday_group(self, ctx):
+        """
+        Kategori for styring av bursdagsfunksjonalitet
+        """
+
+        if ctx.invoked_subcommand is None:
+            await ctx.send_help(ctx.command)
+
+    @commands.is_owner()
+    @birthday_group.group()
+    async def admin(self, ctx):
+        """
+        Kategori for innstillinger
+        """
+
+        if ctx.invoked_subcommand is None:
+            await ctx.send_help(ctx.command)
+
+    @admin.command(name="guild")
+    async def set_guild(self, ctx, guild_id):
+        """
+        Kommando for å sette guild_id i innstillinger
+        """
+        try:
+            self.settings["guild"] = int(guild_id)
+            await ctx.send(f"La til guild med guild id {guild_id} i lista")
+        except KeyError:
+            self.settings["guild"] = ""
+            self.settings["guild"] = int(guild_id)
+        except Exception:
+            return self.bot.logger.error(f"Failed to set guild_id: {guild_id}")
+        self.save_settings(self.settings)
+        self.load_settings()
+
+    @admin.command(name="channel")
+    async def set_channel(self, ctx, channel: discord.TextChannel):
+        """
+        Kommando for å sette channel_id i innstillinger
+        """
+        try:
+            self.settings["channel_id"] = int(channel.id)
+            await ctx.send(f"Satt kanal med kanal id {channel.id} som bursdagskanal")
+        except Exception:
+            return self.bot.logger.error(f"Failed to set channel_id: {channel.id}")
+        self.save_settings(self.settings)
+        self.load_settings()
+
+    @admin.command(name="role")
+    async def set_role(self, ctx, role: discord.Role):
+        """
+        Kommando for å sette bursdagsrolle i innstillinger
+        """
+        try:
+            self.settings["birthday_role_id"] = int(role.id)
+            await ctx.send(f"Satt rolle med id {role.id} som bursdagsrolle")
+        except Exception:
+            return self.bot.logger.error(f"Failed to set birthday_role_id: {role.id}")
+        self.save_settings(self.settings)
+        self.load_settings()
+
+    @tasks.loop(time=BIRTHDAY_CHECK_TIME)
+    async def check_todays_birthday(self):
+        """
+        Funksjon som sjekker om noen har bursdag en gang om dagen på et bestemt tidspunkt
+        """
+
+        today = datetime.now()
+        day = today.day
+        month = today.month
+
+        matches = []
+
+        for user_id, data in self.data_cache.items():
+            try:
+                b_day, b_month = map(int, data["birthday"].split("."))
+
+                if b_day == day and b_month == month:
+                    try:
+                        guild_id = self.settings.get("guild")
+                        guild = self.bot.get_guild(guild_id)
+                    except AttributeError:
+                        self.bot.logger.error("Guild not found")
+                        return
+
+                    member = guild.get_member(int(user_id))
+
+                    if member:
+                        matches.append(member.mention)
+                        role = discord.utils.get(guild.roles, id=self.settings.get("birthday_role_id"))
+                        if role:
+                            await member.add_roles(role)
+                    else:
+                        matches.append(data["username"])
+
+            except (ValueError, KeyError):
+                self.bot.logger.error(f"Invalid birthday format for user {user_id}: {data.get('birthday')}")
+
+        if matches:
+            birthday_list = "\n".join([f"🎂 {name}" for name in matches])
+            embed = discord.Embed(
+                title="🎉 Dagens bursdagsbarn! 🎉",
+                description=birthday_list,
+                color=discord.Color.gold(),
+            )
+            embed.set_footer(text="Gratulerer med dagen!")
+            channel = self.bot.get_channel(self.settings.get("channel_id"))
+            if channel:
+                await channel.send(embed=embed)
+
+    @tasks.loop(time=BIRTHDAY_ROLE_TIME)
+    async def remove_birthday_roles(self):
+        """
+        Fjerner bursdagsrollen fra alle brukere hver dag ved midnatt
+        """
+        guild = self.bot.guilds[0]
+        role = discord.utils.get(guild.roles, id=self.settings.get("birthday_role_id"))
+        if not role:
+            return
+
+        for user_id in self.data_cache:
+            member = guild.get_member(int(user_id))
+            if member and role in member.roles:
+                try:
+                    await member.remove_roles(role)
+                except discord.Forbidden as e:
+                    self.bot.logger.error(f"Failed to remove 'årsdag' role from {member.name}: {e}")
+
+    @commands.Cog.listener()
+    async def on_member_remove(self, member):
+        """
+        Fjerner bursdagsdata når en bruker forlater serveren
+        """
+        user_id = str(member.id)
+
+        if user_id in self.data_cache:
+            del self.data_cache[user_id]
+            self.save_data(self.data_cache)
+            self.bot.logger.debug(f"Birthday from {member.name} deleted")
+
+    @check_todays_birthday.before_loop
+    @remove_birthday_roles.before_loop
+    async def before_task(self):
+        await self.bot.wait_until_ready()
+
+
+def check_files(bot):
+    files = [
+        {
+            f"{bot.data_dir}/birthday/innstilinger.json": {
+                "guild": "",
+                "channel_id": "",
+                "birthday_role_id": "",
+            }
+        },
+        {f"{bot.data_dir}/birthday/birthdays.json": {}},
+    ]
+
+    folder = f"{bot.data_dir}/birthday"
+    if not os.path.exists(folder):
+        os.makedirs(folder)
+
+    for i in files:
+        for file, default in i.items():
+            if not os.path.exists(file):
+                with open(file, "w", encoding="utf8") as outfile:
+                    json.dump(default, outfile)
+
+
+async def setup(bot):
+    check_files(bot)
+    await bot.add_cog(Birthday(bot))
diff --git a/launcher.py b/launcher.py
index ca61b05..119296e 100644
--- a/launcher.py
+++ b/launcher.py
@@ -94,7 +94,7 @@ async def on_ready(self):
 
     async def setup_hook(self):
         extensions = ["cogs.norprog", "cogs.misc", "cogs.poeng", "cogs.bokmerker",
-                      "cogs.errors", "cogs.github", "cogs.broder", "cogs.workplace"]
+                      "cogs.errors", "cogs.github", "cogs.broder", "cogs.workplace", "cogs.birthday"]
         for extension in extensions:
             try:
                 self.logger.debug("Loading extension %s", extension)
@@ -102,6 +102,8 @@ async def setup_hook(self):
             except Exception as _e:
                 self.logger.exception("Loading of extension %s failed: %s", extension, _e)
 
+        await self.tree.sync()
+
     async def close(self):
         self.logger.info("Logging out")
         await super().close()