AWS Certificate Manager (ACM) Auto-Renew with Slack notify & approval

Who’s it for

• SRE/DevOps teams managing many ACM certs.
• Cloud ops who want hands-off renewals with an approval step in Slack.
• MSPs that need auditable reminders and renewals on schedule.

How it works / What it does

1. Schedule Trigger – runs daily (or your cadence).
2. Get many certificates – fetches ACM certs (paginate if needed).
3. Filter: expiring in next 7 days – keeps items where:
   • NotAfter before today + 7d
   • NotBefore before today (already valid)
4. Send message and wait for response (Slack) – posts a certificate summary and pauses until Approve/Reject.
5. Renew a certificate – on Approve, calls the renew action for the item.

How to set up

1. Credentials
   • AWS in n8n with permissions to list/read/renew certs.
   • Slack OAuth (bot in the target channel).
2. Schedule Trigger
   • Set to run once per day (e.g., 09:00 local).
3. Get many certificates
   • Region: your ACM region(s).
   • If you have several regions, loop regions or run multiple branches.
4. Filter (IF / Filter node)
   • Add these two conditions (AND):
     • {{ $json.NotAfter.toDateTime('s') }} is before {{ $today.plus(7,'days') }}
     • {{ $json.NotBefore.toDateTime('s') }} is before {{ $today }}
5. Slack → Send & Wait

   • Message (text input):

     :warning: *ACM Certificate Expiry Alert* :warning:
     
     *Domain:* {{ $json.DomainName }}
     *SANs:* {{ $json.SubjectAlternativeNameSummaries }}
     *ARN:* {{ $json.CertificateArn }}
     *Algo:* {{ $json.KeyAlgorithm }}
     *Status:* {{ $json.Status }}
     *Issued:* {{ $json.IssuedAt | toDate | formatDate("YYYY-MM-DD HH:mm") }}
     *Expires:* {{ $json.NotAfter | toDate | formatDate("YYYY-MM-DD HH:mm") }}
     
     Approve to start renewal.
     

   • Add two buttons: Approve / Reject (the node will output which was clicked).

6. Renew a certificate
   • Map the CertificateArn from the Slack Approved branch.

Requirements

• n8n (current version with Slack Send & Wait).
• AWS IAM permissions (read + renew ACM), e.g.:
  • acm:ListCertificates, acm:DescribeCertificate, acm:RenewCertificate (plus region access).
• Slack bot with permission to post & use interactivity in the target channel.

How to customize the workflow

• Window size: change 7 to 14 or 30 days in the filter.
• Catch expired: add an OR path {{ $json.NotAfter.toDateTime('s') }} is before {{ $today }} → send a red Slack alert.
• Auto-renew w/o approval: bypass Slack and renew directly for low-risk domains.
• Multiple regions/accounts: iterate over a list of regions or assume roles per account.
• Logging: add a Google Sheet/DB append after Slack click with user, time, result.
• Escalation: if no Slack response after N hours, ping @oncall or open a ticket.

Notes

• The Slack node pauses execution until a button is clicked—perfect for change control.
• Time conversions above assume NotAfter/IssuedAt are Unix seconds ('s'). Adjust if your data differs.