Colon CTO is a public Telegram group — anyone can join without invitation. Your phone number is never visible to other members unless you've made it public in your Telegram privacy settings. You can leave at any time with a single tap.

No. Telegram never notifies your contacts when you join or leave a group. Other members inside Colon CTO can see your username only if you post — your membership is not visible to anyone outside the group.

We verify every listing is publicly accessible, has a minimum member count, and exclude groups Telegram has marked as harmful. Colon CTO currently has 65 members and is marked as active. If you've joined Colon CTO and noticed something suspicious — a review on this page helps others stay safe.