This package provides a verified-style n8n community node for Lettr.

• Source logo file (edit this): assets/logo.svg
• n8n node icon file (auto-generated from source on build): nodes/Lettr/lettr.svg

To apply your custom SVG logo:

npm run sync:logo
npm run build

• Email
  • Send
  • Get
• Domain
  • Get Many
• Template
  • Get Many, Get, Create, Update, Delete, Get HTML, Get Merge Tags
• Folder
  • Get Many
• Webhook
  • Get Many
• Campaign
  • Get Many, Get, Get Events, Send, Schedule, Unschedule
• Audience Contact
  • Get Many, Get, Create, Create Many, Update, Delete, Attach/Detach List, Bulk Attach/Detach Lists, Subscribe/Unsubscribe Topic, Bulk Subscribe/Unsubscribe Topics
• Audience List
  • Get Many, Get, Create, Update, Delete, Delete Many
• Audience Topic
  • Get Many, Get, Create, Update, Delete
• Audience Property
  • Get Many, Get, Create, Update, Delete
• Audience Segment
  • Get Many, Get, Create, Update, Delete

A template is either transactional (the default — receipts, password resets, alerts) or campaign (marketing sent to an audience list). A campaign can only send a template whose purpose is campaign, and the purpose cannot be changed after creation — a newsletter created with the default has to be rebuilt.

Set it under Additional Fields → Purpose when creating a template. Template Get Many can filter by it, so purpose = Campaign lists exactly the templates a campaign is able to send.

The Folder resource lists the folders templates are filed into, with each folder's purpose and template count. It is the only way to discover a folder ID: without it the choice is to leave Folder ID empty and accept whichever folder the API picks, or to hardcode an integer read out of an app URL.

A folder's purpose is independent of its templates'. Filing a template in a campaign folder does not make the template a campaign template.

Template Get Many accepts a Folder ID filter, which turns reconciling a bulk import into one call rather than a Get per template. A folder outside the resolved project is an error rather than an empty list, so a wrong ID cannot be mistaken for an empty folder.

Imported templates render asynchronously, so a template can exist before it is sendable. Template responses carry preparation_status — pending, ready or failed — and the node passes it through untouched.

After an update the previous render keeps serving until the new one settles, so a pending template still sends; it just isn't serving the new content yet.

Email → Send → Additional Fields → Idempotency Key makes a send safe to retry. Reuse the same value and the API returns the original result instead of delivering a second email.

This matters in a workflow: an n8n retry after a timeout has no way of knowing whether the first attempt actually landed. Derive the key from what the send is about — an order ID, an invoice number — rather than from a timestamp or random value, which defeat the point on a retry. Keys are kept 24 hours and scoped per team and API key.

The field is shared with Schedule in the UI but only applies to Send: a scheduled transmission is created once and then cancelled or edited by ID, so there is nothing to replay.

Audience Contact → Create Many has two input modes.

Email List (default) sends one list of addresses, with the same lists, topics and properties applied to everyone. This is the original behaviour — workflows built before per-contact rows existed keep sending the identical payload.

Per-Contact Rows takes a JSON array where each contact carries its own data:

[
  {
    "email": "cara@example.com",
    "properties": { "plan": "pro" },
    "list_ids": ["01h-vip"],
    "topics": [{ "id": "01h-newsletter", "subscription": "opt_in" }]
  },
  { "email": "dan@example.com" }
]

Row values stack on top of anything in Batch Options, with one exception: a row-level topic opt_out beats a batch-level opt_in. That is the point of opt_out — a topic configured to auto-subscribe new contacts can be suppressed for specific people in the same request, instead of a second cleanup call.

Update Existing (off by default) controls only whether properties are merged into contacts that already exist. Existing contacts are attached to the requested lists and topics either way.

The node returns the API response as-is. Two things to watch:

• A successful run does not mean every row landed. The API answers 201 even when rows were skipped. Check data.error_count and data.errors[] — each error carries index (zero-based into the rows you submitted), email, error_code and error. Branch on error_count with an If node if partial failure should stop the workflow.
• already_existed and updated overlap. They answer different questions — "was it already there?" and "did we change it?" — so they do not sum to the row count. A contact that existed and got attached to a list is counted in both.

data.contacts[] gives back { id, email, created } for every contact in submission order, so a follow-up node can use the IDs without a lookup.

Use a Lettr API key from your Lettr account.

• Credential type: Lettr API
• Auth header: Authorization: Bearer <api_key>

npm install
npm run build

npm install /absolute/path/to/n8n-nodes-lettr

Then restart n8n.

• Uses official Lettr REST endpoints at https://app.lettr.com/api
• Includes credential test call (GET /domains)
• Includes pagination controls for list operations
• Runtime has no third-party dependencies

• Lettr API introduction
• Send email
• Get email request
• List domains
• List templates
• List webhooks
• Audience API