The Join Captcha Bot

What it does

The Join Captcha Bot guards Telegram groups against spam accounts. Whenever someone joins, the bot posts a captcha challenge and starts a timer. Users who solve it stay; users who ignore it are removed when the time runs out. If the same account joins five times in a row without ever solving the challenge, it is treated as a bot and banned outright.

Any message containing a link sent by a newcomer before the captcha is solved is treated as spam and deleted. The bot also cleans up its own service messages so the chat stays readable. Everything is configurable by group administrators, either inside the group or from a private chat through /connect.

Features

• 🧩 Several captcha modes — animated video, numeric, hex, ASCII, math, a custom poll, or a single button via /captcha_mode.
• ⏱️ Adjustable timer and difficulty — /time sets how long newcomers get, /difficulty sets levels 1 to 5.
• 🚫 Flexible punishments — /restriction chooses kick, ban or mute for users who fail.
• 🔗 Link filtering — newcomer links are deleted automatically, and /url_disable blocks links for everyone.
• 👋 Custom welcome message — /welcome_msg greets verified members, with optional auto-deletion.
• ⚙️ Remote configuration — /connect lets admins tune a group from a private chat; /checkcfg shows current settings.

How to use

1. Add the bot to your group and grant it admin rights to ban users and delete messages.
2. Send /enable in the group to turn captcha protection on.
3. Pick a challenge with /captcha_mode and set the timer with /time.
4. Choose what happens to failures with /restriction.
5. Review everything with /checkcfg, or manage it privately via /connect.