I am new to Twillio. I just bought a number and I am using API to send text messages through that number. But the recipient is able to reply back to that number. How can I disable incoming text messages?
You can disable text messaging completely for a number, but you cannot selectively disable incoming texts or texts from a specific number.
See this for more information: https://help.twilio.com/articles/223181648-Is-there-a-way-to-block-incoming-SMS-on-my-Twilio-phone-number