Telegram bots and Discord webhooks

A Telegram bot is created by messaging @BotFather, which returns a token; your server then calls the Bot API over HTTPS (sendMessage with a chat id) to post into a private chat, group or channel. Bots can only message people who have started a chat with them first, and Telegram asks bots to stay under about 30 messages a second overall and 20 a minute in any one group.

A Discord webhook is a secret URL created in a channel's settings; posting JSON to it (text, embeds, a name and an avatar) drops a message into that channel with no bot account needed. Slack's incoming webhooks work the same way. They suit internal alerts rather than customers: anyone holding the URL or token can post, so keep it in environment variables, and expect rate limits during bursts.