Email Notifications

Email is the most universal notification channel. Reoclo connects to any SMTP server you control — Gmail, Microsoft 365, AWS SES, Postmark, Mailgun, SendGrid, your own Postfix — and sends one message per event to a fixed recipient list.

When to use it

• You want a permanent record in everyone’s inbox
• You’re sending to people who don’t live in chat (executives, customers, on-call rotations without a paging tool)
• You need an audit trail your SIEM already ingests via email gateways

For real-time chat, prefer Slack or Microsoft Teams. For paging, prefer PagerDuty or OpsGenie.

Prerequisites

• An SMTP server you can authenticate to (host, port, optional username/password)
• A verified From address — your SMTP provider must allow sending from this address, or recipients will see SPF/DKIM failures and route the message to spam
• One or more recipient addresses

Step 1 — Prepare your SMTP credentials

Pick the row that matches your provider:

Provider	Host	Port	TLS	Auth notes
Gmail / Google Workspace	smtp.gmail.com	587	Yes	Use an App Password — regular passwords are blocked
Microsoft 365	smtp.office365.com	587	Yes	App password / OAuth2 required when MFA is on
AWS SES	email-smtp.<region>.amazonaws.com	587	Yes	Generate SMTP credentials from the SES console (not your AWS access key)
Postmark	smtp.postmarkapp.com	587	Yes	Use a Server API Token as both username and password
Mailgun	smtp.mailgun.org	587	Yes	Use the SMTP credentials shown on your domain page
SendGrid	smtp.sendgrid.net	587	Yes	Username is apikey, password is the API key

Tip

If your provider uses port 465 (implicit TLS) you can still set Use TLS on — Reoclo upgrades the connection with STARTTLS on 587 and uses implicit TLS on 465.

Step 2 — Create the channel in Reoclo

Dashboard

1. Open Settings → Notification Channels

2. Click Add Channel and pick Email

3. Fill in the form:

   Field	Required	Description
   SMTP host	Yes	e.g., smtp.gmail.com
   SMTP port	No (587)	587 for STARTTLS, 465 for implicit TLS, 25 only for trusted internal relays
   Username	No	Leave blank for unauthenticated relays
   Password	No	Stored encrypted at rest
   Use TLS	Yes (on)	Leave on unless you’ve explicitly chosen a plaintext internal relay
   From address	Yes	The verified sender, e.g., [email protected]
   Recipients	Yes	One or more addresses; one message is sent per recipient list, not per address

4. Click Send Test — Reoclo sends a [TEST] email and surfaces any SMTP error in the form. The channel cannot be saved until the test succeeds.

5. Choose which events this channel receives (defaults are a good starting point).

6. Save.

CLI

reoclo channels create email --from-file alerts-email.yaml

kind: email
name: ops-alerts
config:
  smtp_host: email-smtp.us-east-1.amazonaws.com
  smtp_port: 587
  smtp_username: ${env:SES_SMTP_USER}
  smtp_use_tls: true
  smtp_from_address: [email protected]
  recipients:
    - [email protected]
    - [email protected]
secret: ${env:SES_SMTP_PASSWORD}
events:
  deploy_failed: true
  monitoring_uptime_down: true
  incident_created: true

Then test:

reoclo channels test <channel-id>
# or override the recipient for a one-off send
reoclo channels test <channel-id> --to [email protected]

Message format

Reoclo sends one HTML email per event. The Subject matches the event summary; the body is a short HTML rendering with the relevant context (deployment name, server, error excerpt). All messages come from your configured From address.

Troubleshooting

Symptom	Cause	Fix
535 Authentication failed	Wrong username/password or app password not generated	Generate an app password (Gmail/M365) or regenerate SMTP credentials
530 Must issue a STARTTLS command first	TLS disabled but required	Turn Use TLS back on
Emails land in spam	Missing SPF/DKIM for the From domain	Configure SPF + DKIM at your DNS provider, or send from a verified provider domain
550 Sender address rejected	From address not verified with your SMTP provider	Verify the address in your provider’s console
Test passes, real events silent	Event toggles disabled	Open the channel and turn on the events you care about

Next Steps

• Set up Slack for real-time chat delivery alongside email
• Hook events into Alert Rules so monitor thresholds trigger your email channel