Get started →

Install

npm install maildeno
# or
yarn add maildeno
# or
pnpm add maildeno
# or
bun add maildeno

Configure the client

import { MaildenoClient } from "maildeno"

const client = new MaildenoClient({
  // Required — obtain from Dashboard → API Keys → Create Key
  apiKey: process.env.MAILDENO_API_KEY!,

  // Optional — request timeout in ms, defaults to 30000
  timeout: 10_000,
})

Configuration options

Option Type Default Description

apiKey

string

—

Required. Your Maildeno API key.

timeout

number

30000

Request timeout in milliseconds. Throws TIMEOUT if exceeded.

Client lifecycle

The MaildenoClient is stateless — it holds only configuration. There is no connection pool to manage. Instantiate it once at module level and reuse across requests:

// Module-level singleton — recommended
const maildeno = new MaildenoClient({ apiKey: process.env.MAILDENO_API_KEY! })

export async function sendWelcomeEmail(name: string, to: string) {
  const html = await maildeno.renderHtml("template-id", {
    merge_tags: { text: { name } },
  })
  // ... send html via your email provider
}

Node.js version requirements

Node version Notes

18+

Native fetch available — no polyfill needed.

< 18

Install node-fetch and polyfill globalThis.fetch before importing the SDK.

Node.js < 18 polyfill

npm install node-fetch
import fetch from "node-fetch"
;(globalThis as any).fetch = fetch

// Now import the SDK
import { MaildenoClient } from "maildeno"

Other runtimes

Runtime Notes

Bun

Native fetch — works out of the box.

Deno

Native fetch — import from npm specifier: import { MaildenoClient } from "npm:maildeno"

Cloudflare Workers

Native fetch — works out of the box. Keep the API key in a secret binding, not in source.

Browser

Native fetch — but never expose your API key client-side. See Frontend usage.