SMTP to Telegram

Forked from KostyaEsmukov/smtp_to_telegram package.

smtp_to_telegram is a small program which listens for SMTP and sends all incoming Email messages to Telegram.

Say you have a software which can send Email notifications via SMTP. You may use smtp_to_telegram as an SMTP server so the notification mail would be sent to the chosen Telegram chats.

Getting started

1. Create a new Telegram bot: https://core.telegram.org/bots#creating-a-new-bot.
2. Open that bot account in the Telegram account which should receive the messages, press /start.
3. Retrieve a chat id with curl https://api.telegram.org/bot<BOT_TOKEN>/getUpdates. If you don't see chat id, try writing one more message to the bot.
4. Repeat steps 2 and 3 for each Telegram account which should receive the messages.
5. Create env_file from env_file.example and fill it with your data.
6. Start a docker container:

docker compose up

You may use localhost:25 as the target SMTP address. No TLS or authentication is required.

The default Telegram message format is:

From: {from}\\nTo: {to}\\nSubject: {subject}\\n\\n{body}\\n\\n{attachments_details}

A custom format might be specified as well:

ST_TELEGRAM_CHAT_IDS=<CHAT_ID1>,<CHAT_ID2>
ST_TELEGRAM_BOT_TOKEN=<BOT_TOKEN>
ST_TELEGRAM_MESSAGE_TEMPLATE="Subject: {subject}\\n\\n{body}"
ST_SMTP_ALLOWED_HOSTS=cvzilla.net,example.com