A script to delete all messages in Telegram group topic using Telethon.

delete_topic_messages.py

# requires-python = ">=3.13"
# dependencies = [
#   "telethon",
# ]
# ///
import asyncio
from os import getenv

from telethon import TelegramClient

api_id = int(getenv("TG_API_ID"))
api_hash = getenv("TG_API_HASH")
group_id = int(getenv("TG_CHAT_ID"))
topic_id = int(getenv("TG_TOPIC_ID"))
min_id = int(getenv("TG_MIN_ID")) if getenv("TG_MIN_ID") else None
max_id = int(getenv("TG_MAX_ID")) if getenv("TG_MAX_ID") else None

if not all([api_id, api_hash, group_id, topic_id]):
    print("API_ID, API_HASH, GROUP_ID, and TOPIC_ID must be set")
    exit(1)


_loop = asyncio.new_event_loop()
asyncio.set_event_loop(_loop)
client = TelegramClient("telethon_session", api_id, api_hash, loop=_loop)


async def main():
    await client.start()
    print(f"Deleting messages from topic {topic_id} in chat {group_id}...")

    deleted_count = 0
    message_ids = []

    target = await client.get_entity(group_id)

    iter_args = {
        "reply_to": topic_id,
        "reverse": True,
    }

    if min_id is not None:
        iter_args["min_id"] = min_id
    if max_id is not None:
        iter_args["max_id"] = max_id

    async for message in client.iter_messages(target, **iter_args):
        message_ids.append(message.id)

        # Delete in batches of 100 messages
        if len(message_ids) == 100:
            try:
                await client.delete_messages(group_id, message_ids)
                print(f"Deleted batch of {len(message_ids)} messages")
                deleted_count += len(message_ids)
                message_ids = []
                await asyncio.sleep(0.5)  # small delay to avoid rate limits
            except Exception as e:
                print(f"Error deleting batch: {e}")
                await asyncio.sleep(2)

    if message_ids:
        try:
            await client.delete_messages(group_id, message_ids)
            print(f"Deleted final batch of {len(message_ids)} messages")
            deleted_count += len(message_ids)
        except Exception as e:
            print(f"Error deleting final batch: {e}")

    print(f"✅ Done. Total deleted: {deleted_count}")
    await client.disconnect()


asyncio.run(main())

mise.toml

[tools]
python = "3.14"
"aqua:astral-sh/uv" = "latest"

[env]
TG_API_ID = 
TG_API_HASH = 
TG_CHAT_ID = 
TG_TOPIC_ID =