Listmonk Newsletter Integration

Send newsletters to your subscribers by composing an email in neomd. Address it to a virtual trigger address (e.g. listmonk@ssp.sh), and neomd creates a Listmonk campaign via API instead of sending via SMTP. Inspired by HEY World.

How it works

1. Compose an email as usual (c)
2. Set the To field to a configured trigger address (e.g. listmonk-newsletter@ssp.sh)
3. Write your newsletter in Markdown — it becomes the campaign body
4. The pre-send screen shows “Newsletter via Listmonk” with the target list IDs and schedule delay
5. Press enter — neomd creates a campaign in Listmonk and schedules it

The campaign is created as a draft, then immediately set to scheduled status. Listmonk handles the actual delivery to your subscribers (via Amazon SES or whatever messenger you configured).

Configuration

Add a [listmonk] section to your config.toml:

[listmonk]
url = "https://list.ssp.sh"
api_user = "sspaeti-api"
api_token = "${LISTMONK_API_TOKEN}"
delay_minutes = 30

[[listmonk.triggers]]
address = "listmonk-newsletter@ssp.sh"
list_ids = [2]

[[listmonk.triggers]]
address = "listmonk-book@ssp.sh"
list_ids = [4]
template_id = 5  # optional: override default template (e.g. "Book Update Template")

[[listmonk.triggers]]
address = "listmonk@ssp.sh"
list_ids = [2, 4]  # send to all lists

Per-trigger fields:

Per-list templates

Each trigger can pin its own Listmonk template. For example, if you have a generic “Newsletter Template” set as the Listmonk default (ID 4) and a “Book Update Template” (ID 5) you only want to use for book announcements, set template_id = 5 on the listmonk-book trigger and leave the others untouched — they fall back to the Listmonk default. Look up template IDs via the API:

curl -u "admin:token" https://list.ssp.sh/api/templates | jq '.data[] | {id, name, is_default}'

Trigger addresses

Each [[listmonk.triggers]] entry maps a virtual email address to one or more Listmonk list IDs. You can configure multiple triggers to target different lists:

• listmonk-newsletter@ssp.sh → sends to your newsletter list only
• listmonk-book@ssp.sh → sends to your book subscribers only
• listmonk@ssp.sh → sends to both lists at once

The trigger address doesn’t need to be a real mailbox — neomd intercepts it before any SMTP delivery.

Getting your list IDs

List IDs are visible in the Listmonk admin UI, or via the API:

curl -u "admin:token" https://list.ssp.sh/api/lists | jq '.data.results[] | {id, name}'

Pre-send screen

When the To address matches a trigger, the pre-send review changes:

• Header shows “Newsletter via Listmonk” instead of “Ready to send”
• Displays the target list IDs, template ID (if overridden), and schedule delay
• Help bar shows enter schedule campaign instead of enter send

How it looks

When sent in neomd:

And in Listmonk itself:

Content

The email body (Markdown) is sent as-is with content_type: "markdown" — Listmonk converts it to HTML using its own template engine. The compose subject becomes the campaign subject.

API details

neomd uses two Listmonk API calls:

1. POST /api/campaigns — creates campaign in DRAFT status with send_at set to now + delay_minutes; includes template_id only when the matching trigger sets a non-zero override (otherwise Listmonk applies its default template)
2. PUT /api/campaigns/{id}/status — sets status to scheduled

Authentication is HTTP Basic Auth. The campaign name is auto-generated as "{subject} - {timestamp}".