Lettr Node.js SDK

Official Node.js SDK and CLI tools for the Lettr transactional email service.

Packages

Package	Description
lettr	Core SDK — type-safe API client for emails, templates, domains, webhooks, audience, and campaigns
lettr-kit	CLI tool for managing Lettr email templates locally

Quick Start

npm install lettr

import { Lettr } from "lettr";

const client = new Lettr(process.env.LETTR_API_KEY!);

const { data, error } = await client.emails.send({
  from: "sender@example.com",
  to: ["recipient@example.com"],
  subject: "Welcome!",
  html: "<h1>Hello!</h1>",
});

if (error) {
  console.error(error.message); // error.type: "validation" | "api" | "network"
} else {
  console.log(data.request_id);
}

Every method returns a Result<T> ({ data, error }) — the SDK never throws for API or network failures.

Documentation

📚 docs.lettr.com/quickstart/nodejs — full guides for sending, templates, domains, webhooks, audience, and campaigns, plus the API reference.

CLI (lettr-kit)

npm install -g lettr-kit

lettr-kit init          # Interactive setup — creates lettr.json
lettr-kit list          # List all templates with sync status
lettr-kit pull          # Pull templates as HTML files
lettr-kit pull --all    # Pull all templates without prompting

Development

This is a monorepo using Bun workspaces.

bun install
bun run build
bun run test

License

MIT