r/TGuard

We build TGuard (@channel_guardian_bot). Bot attacks on Telegram channels are basically our whole world, so here's what we've learned building defenses against them.

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Three attack types, very different problems

The obvious one is a bots swarm — someone orders 10,000 fakes and they all hit your channel in an afternoon. Engagement craters, Telegram's algorithm notices, sponsors ask questions. Hard to miss, at least.

Worse in some ways are prize hunters: accounts built to look real — profile photo, some posts, real-ish names — created to enter giveaways and contests. They slip past naive bot filters. We see a lot of these.

Then there's the slow drip bot attack, which is the nastiest. A few hundred fakes per day. Nothing spikes, nothing looks alarming, and three weeks later your real engagement rate is half of what it was. These are the hardest to explain to a sponsor after the fact.

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What we built to protect channels and groups

Antivirus. Every new subscriber gets cross-referenced against a database of accounts we've seen participating in bot attacks on other channels. Not "this looks suspicious" — actual attack history. 10M+ accounts in there. It catches prize hunters too, not just obvious bot farms, because those accounts keep showing up across multiple attacks.

Rate limiting. You set a ceiling — say, 200 new subscribers per hour based on your normal growth. A bots swarm blows past that threshold and the excess gets auto-removed. Simple and effective for mass attacks. One real gotcha: remember to raise the limit before you run ads or a giveaway.

CAPTCHA. The most aggressive way to protect a channel or group from bots — every new subscriber solves a challenge before they're in. Nearly 100% effective. The cost is friction: some real people won't bother on a public channel. We'd call it overkill for normal operation and essential if you're actively under attack. Supported for both: public and private channels and groups.

Selective cleanup. After a bot attack, you don't want to delete everyone who joined that week. The cleanup tool lets you filter the subscriber list by join date, last seen, username patterns, whatever, and remove just the junk. Surgical rather than scorched earth.

There's also an SOS mode — one button enables a default protection stack if you need cover fast and don't want to tune settings in the middle of an incident. Fine as a first response, but worth revisiting once things calm down.

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Honest recommendation

For most channels: antivirus on permanently, rate limit set to normal growth plus some headroom. That's it. Handles the majority of bot attacks without touching the user experience.

CAPTCHA only if you're under real sustained attack or about to run something high-stakes where fake entrants are a specific problem.

Clean up after every major promo. There's always some leakage, and a few minutes of cleanup right after is a lot cheaper than discovering the problem months later.

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Happy to answer questions, especially about slow drip attacks — that's where most people get burned without realizing it.