Projects & Folders

Projects and folders help you organize your email templates. Use projects to separate templates by brand, product, or team, and use folders within projects to group related templates together.

Overview

The template hierarchy in Lettr works as follows:

Team
└── Project (e.g., "Marketing Site")
    ├── Folder (e.g., "Transactional")
    │   ├── Template: welcome-email
    │   ├── Template: password-reset
    │   └── Template: order-confirmation
    └── Folder (e.g., "Newsletters")
        ├── Template: weekly-digest
        └── Template: product-updates

Every team has a default project created automatically. Templates are organized into projects and folders, which you can reference when working with the API.

Transactional vs. Marketing Templates

Every template belongs to one of Lettr’s two modes: Transactional (sent via the API or SMTP) or Marketing (used by campaigns). Folders are mode-scoped too — a folder holds templates of one mode, and the folder pickers in the move and duplicate dialogs only show folders of the mode you’re browsing, so you can’t accidentally move a marketing email into a transactional folder. A few behaviors that follow from this:

Copying to the other mode — Use the Copy to Transactional / Copy to Marketing action on a template to create a copy in the other mode. The copy is named “name (Copy)”, gets a new unique slug, and carries over all versions and merge tags. It lands in your current folder if that folder already belongs to the target mode, otherwise in the project’s default folder for that mode.
Duplicating into a folder — A duplicated template takes on the mode of the folder you duplicate it into, not the mode of the original.
Deleting a folder keeps its templates — Templates in a deleted folder are not deleted with it. Each one is moved to the project’s default folder for its mode.

When sending emails with templates, you can specify which project to use:

await lettr.emails.send({
  from: 'you@example.com',
  to: ['recipient@example.com'],
  subject: 'Welcome',
  template_slug: 'welcome-email',
  project_id: 123
});

If you don’t specify a project_id, Lettr uses the default project for your team.

Listing Templates by Project

When retrieving templates via API, templates are returned with their project context:

curl -X GET "https://app.lettr.com/api/templates" \
  -H "Authorization: Bearer lttr_xxxxxxxxxxxx"

Response includes project information:

{
  "data": [
    {
      "id": 1,
      "name": "Welcome Email",
      "slug": "welcome-email",
      "project_id": 123,
      "folder_id": 3,
      "created_at": "2026-01-10T09:00:00Z",
      "updated_at": "2026-01-15T14:30:00Z"
    },
    {
      "id": 2,
      "name": "Order Confirmation",
      "slug": "order-confirmation",
      "project_id": 123,
      "folder_id": 5,
      "created_at": "2026-01-12T11:00:00Z",
      "updated_at": "2026-01-20T08:15:00Z"
    }
  ]
}

You can scope both endpoints to a specific project by adding ?project_id=123. If omitted, your team’s default project is used.

Default Project

Every team has a default project. This project:

Cannot be deleted
Receives templates when no project is specified
Is used when API calls don’t include a project_id

Best Practices

Project Organization

By Brand: Create separate projects for each brand if you send emails from multiple brands
By Product: Separate projects for different products or services
By Environment: Consider separate projects for production vs. staging if testing extensively

Folder Organization

By Email Type: Group transactional, marketing, and notification emails
By Customer Journey: Organize by lifecycle stage (onboarding, engagement, retention)
By Frequency: Separate one-time emails from recurring ones

Naming Conventions

Use consistent naming patterns:

Projects:
- "Acme SaaS"
- "Acme Enterprise"
- "Internal Communications"

Folders:
- "Transactional"
- "Onboarding Sequence"
- "Product Updates"

Templates (slugs):
- welcome-email
- password-reset
- weekly-digest-v2

Template Editor

Create templates with the visual editor

Templates Introduction

Get started with email templates

Template Versions

Manage multiple versions of templates

Storage Domains

Configure custom domains for template assets

Documentation

Quickstart

Learn

Integrations

Resources

Projects & Folders

Overview

Transactional vs. Marketing Templates

Listing Templates by Project

Default Project

Best Practices

Project Organization

Folder Organization

Naming Conventions

Template Editor

Templates Introduction

Template Versions

Storage Domains

​Overview

​Transactional vs. Marketing Templates

​Listing Templates by Project

​Default Project

​Best Practices

​Project Organization

​Folder Organization

​Naming Conventions

​Related Topics

Template Editor

Templates Introduction

Template Versions

Storage Domains

Overview

Transactional vs. Marketing Templates

Listing Templates by Project

Default Project

Best Practices

Project Organization

Folder Organization

Naming Conventions

Related Topics