go-notification

Telegram's Bot API is officially supported, free, and has no rate limits that matter for normal notification traffic. Great for internal alerts and customer-opt-in notifications.

Setup

On Telegram, message @BotFather.
Run /newbot and follow the prompts. You get a bot token like 123456:ABC-DEF....
Have each recipient message your bot (the bot can't DM users first).
To find their chat ID: hit https://api.telegram.org/bot<TOKEN>/getUpdates after they message — message.chat.id is the recipient chat ID.

main.go

import "github.com/gopackx/go-notification/channel/chat/telegram"

notifier.RegisterChannel(telegram.New(telegram.Config{
    Name:     "telegram",
    BotToken: os.Getenv("TELEGRAM_BOT_TOKEN"),
}))

Sending

main.go

import "github.com/gopackx/go-notification/channel/chat"

func (n OrderShipped) Via(u notification.Notifiable) []string {
    return []string{"telegram"}
}

func (n OrderShipped) ToChat(u notification.Notifiable) *chat.Message {
    return chat.NewMessage().
        SetText("*Your order shipped*\nOrder: " + n.OrderID).
        SetParseMode("Markdown")
}

func (u User) RouteNotificationFor(channel string) string {
    if channel == "telegram" {
        return u.TelegramChatID // e.g. "123456789"
    }
    return ""
}

Groups & channels

Groups — add your bot to the group, promote it if needed, then use the group's chat ID (negative number) as the recipient.
Channels — add the bot as an admin. Use the channel's @username or numeric ID.

Configuration reference

Field	Type	Required	Description
`BotToken`	`string`	yes	Bot token from BotFather.
`DefaultChatID`	`string`	no	Fallback chat ID if `RouteNotificationFor` returns empty.
`Name`	`string`	no	Channel name used by `Via()`. Defaults to `"chat"`.
`Timeout`	`time.Duration`	no	HTTP timeout per send. Default: `30s`.

Message options

The chat.Message builder supports:

SetText(string) — message body.
SetParseMode("Markdown" | "MarkdownV2" | "HTML") — rich formatting.
TelegramDisableWebPreview (bool field) — don't expand the first URL into a card.
TelegramReplyToMessageID (int64 field) — reply to a specific message.

Troubleshooting

chat not found — the user hasn't messaged the bot yet, or the chat ID is wrong.
bot was blocked by the user — the recipient blocked your bot. Mark them opted-out in your system.
Markdown doesn't render — unescaped special characters. Either escape them or use HTML parse mode.