Email

The Email channel receives inbound emails via a Postmark webhook (JSON POST) and sends replies via nodemailer over SMTP. It works with any SMTP provider — SendGrid, Mailgun, Gmail, or your own server. Each sender's email address becomes their session identity, giving them persistent memory across every message they send.

How it works

1. A user sends an email to your Postmark inbound address
2. Postmark forwards it as a JSON POST to https://your-gateway/webhooks/email
3. The agent replies via SMTP — in the same email thread

Setup

1. Postmark inbound

1. Create a Postmark account and add an inbound domain
2. Set the inbound webhook URL to https://your-gateway/webhooks/email (add ?secret=YOUR_EMAIL_WEBHOOK_SECRET for verification)
3. Postmark will forward every inbound email as a JSON POST to that URL

2. Environment variables

SMTP_HOST=smtp.sendgrid.net
SMTP_PORT=587
SMTP_USER=apikey
SMTP_PASSWORD=SG.xxxxxxxxxxxx
SMTP_FROM=astra@yourdomain.com
EMAIL_WEBHOOK_SECRET=any-random-string

3. astra.yml (optional)

channels:
  email:
    enabled: true
    defaultAgent: assistant-agent

Session identity

The sender's email address is used as the chatId — the same session and memory system that powers Telegram and Slack conversations. A user who emails from alice@example.com will have persistent memory across every message they send, regardless of subject line.

Email threading

Replies are sent with the correct In-Reply-To and References headers so they appear in the same thread as the user's original message in any email client.

Slash commands

All standard slash commands work in email — sent as the first line of the email body:

Supported providers