Guides
Email notifications
Astrodock can email you when one of your apps goes down and again when it recovers. It's completely optional — add a Resend API key and an address to alert, and the built-in health monitor does the rest.
Optional, off by default
If you don't set an API key, email is silently disabled. The health monitor still runs and you can always see app status in the dashboard — you just won't get emails.
Turn it on
Astrodock sends mail through Resend. Add three values to your
.env:
# ── Email / alerts (optional) ──
ASTRODOCK_RESEND_API_KEY=re_your-resend-api-key
ASTRODOCK_ALERT_EMAIL=you@example.com
ASTRODOCK_EMAIL_FROM=Astrodock <noreply@example.com>| Setting | What it is |
|---|---|
ASTRODOCK_RESEND_API_KEY | Your Resend API key. This is the on/off switch — no key means no email. |
ASTRODOCK_ALERT_EMAIL | Where down/recovery alerts are sent. Use a real inbox you watch. |
ASTRODOCK_EMAIL_FROM | The "from" address alerts come from. Use a domain you've verified in Resend so mail doesn't get marked as spam. |
Get a key from Resend
Create a free Resend account, verify the sending domain you'll use in
ASTRODOCK_EMAIL_FROM, and generate an API key. Paste the key into
ASTRODOCK_RESEND_API_KEY.
Apply the change
Changes to .env take effect on the next start. Bring the stack back up:
docker compose up -dCompose recreates the services that need the new values. Nothing else to do — the health monitor picks up your settings on boot.
What triggers an email
A health monitor inside Astrodock checks every provisioned app on a regular interval. It sends exactly two kinds of message:
- Down alert — sent once after an app fails several consecutive health checks
in a row (a single blip won't page you). The subject looks like
[Astrodock] <App Name> is DOWN. - Recovery notice — sent once the app starts responding again, with roughly how
long it was down. Subject:
[Astrodock] <App Name> has RECOVERED.
You get one down email per outage and one recovery email per recovery — not a check-by-check stream. An app you deliberately stop is treated as stopped, not down, so it won't alert.
Where to see app health
Emails are a convenience layer on top of the dashboard. The Health page in the admin UI shows every app's current status, recent response times, and how long anything has been down — whether or not email is configured.
See The dashboard for a tour of the Health page and the rest of the admin UI.
This is operator alerting, not app email
These notifications go to you, the person running the platform, about platform health. They are not a transactional email service for your apps to send mail to their own users — if an app needs to email its users, give it its own mail provider.
Related
- Watch app status in the dashboard: The dashboard
- Keep your install safe: Backups & restore
- Every config value explained: Install & run