Telegram Duplicate Message Detection Bot

Do you have a Telegram channel and chat that multiple people subscribe to and post to? Then you know how often forwarded posts, images and videos are duplicated by readers intending to be helpful to others.

This Python script introduces a Telegram bot designed to identify and notify about duplicate messages within a specific channel or chat. Utilizing the Telegram Bot API and asynchronous programming (aiohttp and asyncio), the bot offers real-time monitoring to enhance content uniqueness in Telegram communities.


  • Real-Time Duplicate Detection: Monitors messages for duplicates post-bot activation, ignoring historical data.
  • Support for Various Content Types: Handles text, photos, videos, and documents, using unique identifiers for duplication checking.
  • Customizable Message Thresholds: Includes an adjustable text length threshold to ignore brief messages likely to be coincidental duplicates.
  • Resource Management: Employs an OrderedDict for memory-efficient tracking, with a customizable maximum entry limit.
  • Asynchronous Operation: Designed for concurrency, handling multiple messages simultaneously without blocking.
  • Security Conscious: Utilizes hashing to generate unique identifiers for content, ensuring privacy and reducing storage requirements.


  • aiohttp: Asynchronous HTTP client/server framework.
  • asyncio: For writing single-threaded concurrent code using coroutines.
  • re: Module provides regular expression matching operations.
  • logging: Standard Python library for logging.
  • requests: Simple HTTP library for Python.
  • hashlib: Module providing a common interface to many secure hash and message digest algorithms.
  • datetime: Module for manipulating dates and times.
  • telegram.ext: Extension module to help make it easier to use the API.
  • collections.OrderedDict: Dictionary subclass that remembers the order entries were added.
  • unidecode: Module to decode unicode characters to their closest ASCII representation.

Setup Instructions

Install Dependencies: Ensure all required libraries are installed using pip:

pip install python-telegram-bot aiohttp requests unidecode

Telegram Bot Token and Usernames: You will need to have the following details ready:

  • A Telegram Bot Token: Create a bot by talking to BotFather (@BotFather) on Telegram and following the instructions to get a bot token.
  • Your channel’s username: This is the username of the channel where the bot will monitor for duplicate messages.
  • Your chat’s username: This is the username of the chat where the bot will also monitor for duplicates.

Set Privacy Settings: Use the /setprivacy command with BotFather to disable privacy mode, allowing the bot to access all messages.

Bot Permissions: Make sure your bot has the necessary permissions in your channel and chat for managing messages.

Configuration: The bot’s behavior can be adjusted by passing arguments directly. You can also adjust the MIN_TEXT_LENGTH and MAX_LIST_ENTRIES internally for tuning the bot’s sensitivity and memory usage.

Run the Bot: Execute the script with the necessary command-line arguments to start the bot. It will begin monitoring messages, identifying duplicates based on configured thresholds. The bot communicates over HTTPS, eliminating the need for special port configurations. The command-line parameters required to run the bot are as follows:

  • --token: Your Telegram Bot Token obtained from BotFather. This is essential for authenticating requests with the Telegram API.
  • --channel: The username of the Telegram channel where the bot will monitor for duplicate messages. Exclude the “@” symbol from the username.
  • --chat: The username of the Telegram chat (or group chat) for duplicate monitoring. Do not include the “@” symbol.
  • --opmode: Sets the operation mode of the bot. Acceptable values are 0, 1, or 2, where 0 is for watch mode (monitoring only), 1 is for warn mode (sending warnings about duplicates), and 2 is for delete mode (automatically deleting duplicates and warning the user).

To start the bot with these parameters, use the following command format:


How It Works

  • The bot distinguishes between channel and chat messages, applying separate duplicate checks for each context.
  • For media messages (photos, videos, documents), metadata is used to generate a unique identifier. If potential duplication is detected, the bot may download the file to confirm.
  • For text messages, the bot simplifies the content by removing non-alphanumeric characters and converts to lowercase for case-insensitive comparison. A hash of this simplified text is then used for duplication checking.
  • When a duplicate is identified, the bot can (depending on mode) send a warning message to the relevant chat or channel, advising against reposting similar content. The bot attempts to delete this warning message after 60 seconds. It can also delete the offending source message, again depending on the mode.

Security and Privacy

  • The bot does not store personal information or content beyond what is necessary for duplicate detection.
  • Unique identifiers for content are generated using hashing, ensuring content privacy is maintained.


  • The bot does not retrospectively analyze past messages; it only starts monitoring from the point of activation.
  • Although large files are not supported due to Telegram Bot API limitations on downloading size, their metadata is compared.

For more information on the Telegram Bot API and the python-telegram-bot library, consult the official documentation.


This project is licensed under the MIT No Attribution license, a ‘do anything’ license. Usage is ‘caveat emptor’.