diff --git a/moddb/client.py b/moddb/client.py
index f29efb4..2aec5b0 100644
--- a/moddb/client.py
+++ b/moddb/client.py
@@ -1,9 +1,10 @@
 from __future__ import annotations
 
+import os
 import random
 import re
 import sys
-from typing import TYPE_CHECKING, Any, List, Tuple, Union
+from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Union
 
 from curl_adapter import CurlCffiAdapter
 import requests
@@ -12,7 +13,7 @@
 
 from .base import parse_page
 from .boxes import ResultList, Thumbnail, _parse_results
-from .enums import Status, ThumbnailType
+from .enums import AddonCategory, Licence, PlatformCategory, Status, ThumbnailType
 from .errors import ModdbException
 from .pages import Member
 from .utils import (
@@ -41,7 +42,7 @@
 if TYPE_CHECKING:
     from .boxes import Comment, Tag
     from .enums import WatchType
-    from .pages import Engine, Game, Group, Mod, Review, Team
+    from .pages import Addon, Engine, Game, Group, Mod, Review, Team
 
 
 class Message:
@@ -329,7 +330,7 @@ def _request(self, method, url, **kwargs):
         }
 
         req = requests.Request(
-            method, url, headers=headers, cookies=cookies, data=kwargs.pop("data", {})
+            method, url, headers=headers, cookies=cookies, data=kwargs.pop("data", {}), files=kwargs.pop("files", {})
         )
         prepped = self._session.prepare_request(req)
         LOGGER.info("Request: %s", prepped.url)
@@ -1178,6 +1179,228 @@ def downvote_tag(self, tag: Tag) -> bool:
             Whether the downvote was successful
         """
         return self._vote_tag(tag, 1)
+    
+    def _validate_file(self, path: str, max_mbytes: float, accepted_extensions: List[str]):
+        # Check if is file
+        if not os.path.isfile(path):
+            raise ModdbException("Please select a valid file before uploading")
+        
+        # Check file size
+        file_size_mb = os.path.getsize(path) / (1024 * 1024) # b -> mb
+        if file_size_mb <= 0:
+            raise ModdbException("Your file cannot be empty")
+        elif file_size_mb > max_mbytes:
+            raise ModdbException(f"Your file must be less then {max_mbytes}mb")
+        
+        # Check file extension
+        file_ext = os.path.splitext(path)[1]
+        if file_ext not in accepted_extensions:
+            raise ModdbException(f"You cannot select a {file_ext} file only ({', '.join(accepted_extensions)})")
+        
+    def _validate_summary(self, text: str):
+        if not (50 <= len(text) <= 1000):
+            raise ModdbException("The summary must contain at least 50 and at most 1000 characters")
+
+    def _validate_description(self, text: str):
+        if not (100 <= len(text) <= 100000):
+            raise ModdbException("The description must contain at least 100 and at most 100000 characters")
+
+    def _normalize_description(self, description: str):
+        # TODO: implement tinymce checks
+        return description
+
+    def _validate_platforms(self, platforms: List[PlatformCategory]):
+        if not platforms:
+            raise ModdbException("Select the platforms the linked mods relate to")
+        
+    def _validate_post_response(self, html_str: str):
+        soup_obj = soup(html_str)
+        if soup_obj.find("a", id="downloadmirrorstoggle"):
+            return  # Upload successful
+
+        # We are still on the upload form
+        error_tooltip = soup_obj.find("div", class_="tooltip errortooltip clear")
+        if error_tooltip:
+            if error_tooltip.ul:
+                error_list = error_tooltip.ul.find_all("li", recursive=False)
+                errors = "\n".join([f"- {error.text}" for error in error_list])
+            else:
+                # p-tag contains a space at the beginning and a new line at the end
+                errors = f"- {error_tooltip.p.text.strip()}"
+            raise ModdbException(f"Please correct the following: \n{errors}")
+        
+    def _upload_file(self, path: str, url: str):
+        with open(path, 'rb') as f:
+            resp = self._request("POST", url, files={"filedata": f})
+            if resp.json()["error"]:
+                raise ModdbException("An error occurred while trying to upload the add-on")
+            
+    def _prepare_file(self, file_path: str, accepted_exts: List[str], max_size_mb: float):
+        abs_path = os.path.abspath(file_path)
+        self._validate_file(abs_path, max_size_mb, accepted_exts)
+        return abs_path
+        
+    def get_addon_edit_data(self, addon: Addon):
+        html = soup(self._request("GET", f"{addon.url}/edit").text)
+        if not html.find("input", { "name": "formhash" }):
+            raise ModdbException("You do not have permission to edit the requested downloads content")
+        
+        category = AddonCategory(int(html.find("select", id="downloadscategory")
+                      .find_all("option", { "selected": "selected" })[0]["value"]))
+        name = html.find("input", id="downloadsname")["value"]
+        summary = html.find("textarea", id="downloadssummary").text
+        description = html.find("textarea", id="downloadsdescription").text
+        platforms = list(map(lambda c: PlatformCategory(c["value"]), html.find("select", id="downloadsplatforms")
+                        .find_all("option", { "selected": "selected" })))
+        licence = Licence(int(html.find("select", id="downloadslicence")
+                      .find_all("option", { "selected": "selected" })[0]["value"]))
+        credits = html.find("input", id="downloadscredit")["value"]
+        url = html.find("input", id="downloadsnameid")["value"]
+        tags = html.find("input", id="downloadstags")["value"].split(",")
+                
+        return self.EditAddonInfo(category, name, summary, description, platforms, licence, credits, url, tags)
+    
+    def upload_addon(self, mod: Mod, addon_path: str, thumbnail_path: str, category: AddonCategory,
+                     name: str, summary: str, description: str, platforms: List[PlatformCategory],
+                     licence: Licence = Licence.proprietary, credits: str = "", tags: List[str] = []):
+        html = soup(self._request("GET", f"{mod.url}/addons/add").text)
+
+        # Retrieve data for payloads
+        formhash = html.find("input", { "name": "formhash" })["value"]
+        mod_id = html.find("select", class_="right select").find_all("option")[1]["value"]
+
+        # Validations
+        self._validate_summary(summary)
+        self._validate_description(description)
+        self._validate_platforms(platforms)
+        description = self._normalize_description(description)
+
+        # Files
+        addon_exts = html.find("input", id="downloadsfiledata")["accept"].split(",")
+        thumbnail_exts = html.find("input", id="downloadslogo")["accept"].split(",")
+        abs_addon_path = self._prepare_file(addon_path, addon_exts, 52428800 / 1024)
+        abs_thumbnail_path = self._prepare_file(thumbnail_path, thumbnail_exts, 8192 / 1024)
+
+        # Upload addon file
+        self._upload_file(abs_addon_path, f"https://upload.moddb.com/downloads/ajax/upload/{formhash}")
+
+        logo_file = {
+            "logo": open(abs_thumbnail_path, 'rb')
+        }
+        data = {
+            "formhash": formhash,
+            "legacy": 0,
+            "platformstemp": 1,
+            "filedataUp": os.path.basename(abs_addon_path),
+            "category": category.value,
+            "licence": licence.value,
+            "credit": credits,
+            "tags": ",".join(tags),
+            "name": name,
+            "summary": summary,
+            "description": description,
+            "downloads": "Please wait uploading file",
+            "links[]": [*map(lambda p: p.value, platforms), mod_id]
+        }
+
+        resp = self._request("POST", f"{mod.url}/addons/add", data=data, files=logo_file)
+        self._validate_post_response(resp.text)
+        if logo_file["logo"]:
+            logo_file["logo"].close()
+
+    def update_addon(self, addon: Addon, addon_path: Optional[str] = None, thumbnail_path: Optional[str] = None,
+                     category: Optional[AddonCategory] = None, name: Optional[str] = None, summary: Optional[str] = None,
+                     description: Optional[str] = None, platforms: Optional[List[PlatformCategory]] = None,
+                     licence: Optional[Licence] = None, credits: Optional[str] = None, tags: Optional[List[str]] = None,
+                     url: Optional[str] = None):
+        html = soup(self._request("GET", f"{addon.url}/edit").text)
+        if not html.find("input", { "name": "formhash" }):
+            raise ModdbException("You do not have permission to edit the requested downloads content")
+        
+        # Retrieve data for payloads
+        formhash = html.find("input", { "name": "formhash" })["value"]
+        mod_id = html.find("select", class_="right select").find_all("option")[1]["value"]
+        addon_data = self.get_addon_edit_data(addon)
+
+        # Use existing values if not overridden
+        summary = summary or addon_data.summary
+        description = self._normalize_description(description or addon_data.description)
+        name = name or addon_data.name
+        url = url or addon_data.url
+        credits = credits or addon_data.credits
+        tags = tags or addon_data.tags
+        platforms = platforms or addon_data.platforms
+        category = category or addon_data.category
+        licence = licence or addon_data.licence
+
+        self._validate_summary(summary)
+        self._validate_description(description)
+        self._validate_platforms(platforms)
+
+        abs_addon_path = None
+        if addon_path:
+            addon_exts = html.find("input", id="downloadsfiledata")["accept"].split(",")
+            abs_addon_path = self._prepare_file(addon_path, addon_exts, 52428800 / 1024)
+            self._upload_file(abs_addon_path, f"https://upload.moddb.com/downloads/ajax/upload/{formhash}")
+
+        abs_thumbnail_path = None
+        if thumbnail_path:
+            thumbnail_exts = html.find("input", id="downloadslogo")["accept"].split(",")
+            abs_thumbnail_path = self._prepare_file(thumbnail_path, thumbnail_exts, 8192 / 1024)
+
+        logo_file = {
+            "logo": open(abs_thumbnail_path, 'rb') if abs_addon_path else None
+        }
+        data = {
+            "formhash": formhash,
+            "legacy": 0,
+            "platformstemp": 1,
+            "filedataUp": os.path.basename(abs_addon_path) if abs_addon_path else None,
+            "category": category.value,
+            "licence": licence.value,
+            "credit": credits,
+            "tags": ",".join(tags),
+            "nameid": url,
+            "name": name,
+            "summary": summary,
+            "description": description,
+            "downloads": "Please wait uploading file",
+            "links[]": [*map(lambda p: p.value, platforms), mod_id]
+        }
+
+        resp = self._request("POST", f"{addon.url}/edit", data=data, files=logo_file)
+        self._validate_post_response(resp.text)
+        if logo_file["logo"]:
+            logo_file["logo"].close()
+
+    class EditAddonInfo:
+        def __init__(self, category: AddonCategory, name: str, summary: str, description: str, 
+                     platforms: List[PlatformCategory], licence: Licence, credits: str,
+                     url: str, tags: List[str]):
+            self.category = category
+            self.name = name
+            self.summary = summary
+            self.description = description
+            self.platforms = platforms
+            self.licence = licence
+            self.credits = credits
+            self.url = url
+            self.tags = tags
+
+        def __str__(self):
+            return (
+                f"EditAddonInfo(\n"
+                f"  Category: {self.category},\n"
+                f"  Name: {self.name},\n"
+                f"  Summary: {self.summary},\n"
+                f"  Description: {self.description},\n"
+                f"  Platforms: {', '.join(map(str, self.platforms))},\n"
+                f"  Licence: {self.licence},\n"
+                f"  Credits: {self.credits},\n"
+                f"  URL: {self.url},\n"
+                f"  Tags: {', '.join(self.tags)}\n"
+                f")"
+            )
 
 
 class TwoFactorAuthClient(Client):
diff --git a/moddb/enums.py b/moddb/enums.py
index 4f59f44..da3863a 100644
--- a/moddb/enums.py
+++ b/moddb/enums.py
@@ -170,6 +170,44 @@ class Month(enum.Enum):
     december = "12"
 
 
+class PlatformCategory(enum.Enum):
+    """The category of the platform"""
+
+    windows = "Windows|platforms1"
+    mac = "Mac|platforms8"
+    linux = "Linux|platforms7"
+    vr = "VR|platforms35"
+    ar = "AR|platforms36"
+    web = "Web|platforms24"
+    rtx = "RTX|platforms40"
+    flash = "Flash|platforms23"
+    dos = "DOS|platforms19"
+    steamdeck = "SteamDeck|platforms41"
+    ios = "iOS|platforms20"
+    android = "Android|platforms22"
+    metro = "Metro|platforms25"
+    xsx = "XSX|platforms39"
+    xone = "XONE|platforms34"
+    x360 = "X360|platforms2"
+    xbox = "XBOX|platforms18"
+    ps5 = "PS5|platforms38"
+    ps4 = "PS4|platforms32"
+    ps3 = "PS3|platforms4"
+    ps2 = "PS2|platforms17"
+    ps1 = "PS1|platforms16"
+    vita = "VITA|platforms28"
+    psp = "PSP|platforms5"
+    switch = "Switch|platforms37"
+    wiiu = "WiiU|platforms31"
+    wii = "Wii|platforms3"
+    gcn = "GCN|platforms15"
+    n64 = "N64|platforms14"
+    snes = "SNES|platforms13"
+    nes = "NES|platforms12"
+    ds = "DS|platforms6"
+    gba = "GBA|platforms11"
+
+
 # BELOW THIS LINE ENUMS ARE GENERATED AUTOMATICALLY
 # PR changes to scripts/generate_enums.py if you want to
 # change something
diff --git a/scripts/data/enums_base.py b/scripts/data/enums_base.py
index 6976cd3..24aecba 100644
--- a/scripts/data/enums_base.py
+++ b/scripts/data/enums_base.py
@@ -169,6 +169,44 @@ class Month(enum.Enum):
     december = "12"
 
 
+class PlatformCategory(enum.Enum):
+    """The category of the platform"""
+
+    windows = "Windows|platforms1"
+    mac = "Mac|platforms8"
+    linux = "Linux|platforms7"
+    vr = "VR|platforms35"
+    ar = "AR|platforms36"
+    web = "Web|platforms24"
+    rtx = "RTX|platforms40"
+    flash = "Flash|platforms23"
+    dos = "DOS|platforms19"
+    steamdeck = "SteamDeck|platforms41"
+    ios = "iOS|platforms20"
+    android = "Android|platforms22"
+    metro = "Metro|platforms25"
+    xsx = "XSX|platforms39"
+    xone = "XONE|platforms34"
+    x360 = "X360|platforms2"
+    xbox = "XBOX|platforms18"
+    ps5 = "PS5|platforms38"
+    ps4 = "PS4|platforms32"
+    ps3 = "PS3|platforms4"
+    ps2 = "PS2|platforms17"
+    ps1 = "PS1|platforms16"
+    vita = "VITA|platforms28"
+    psp = "PSP|platforms5"
+    switch = "Switch|platforms37"
+    wiiu = "WiiU|platforms31"
+    wii = "Wii|platforms3"
+    gcn = "GCN|platforms15"
+    n64 = "N64|platforms14"
+    snes = "SNES|platforms13"
+    nes = "NES|platforms12"
+    ds = "DS|platforms6"
+    gba = "GBA|platforms11"
+
+
 # BELOW THIS LINE ENUMS ARE GENERATED AUTOMATICALLY
 # PR changes to scripts/generate_enums.py if you want to
 # change something