# postmark

> Official Node.js client library for the Postmark HTTP API - https://www.postmarkapp.com

Latest version **5.1.0** (published 2026-07-10) · MIT license · 0 weekly downloads

## Install

```sh
npm install postmark
pnpm add postmark
yarn add postmark
bun add postmark
```

## Health

**Score 65/100 (B)** — status: active.

Positive: has types; no vulnerabilities; recently updated; high maintenance score; high quality score.

Warnings: low downloads; no esm support.

## Facts

| | |
|---|---|
| Version | 5.1.0 |
| Published | 2026-07-10 |
| First published | 2011-03-25 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | CommonJS |
| Node | >=18.0.0 |
| Dependencies | 0 |
| Unpacked size | 378.3 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 360 |
| Author | Postmark |
| Maintainers | dandigangi_ac, coaldon_ac, smunuswamiac |

## Links

- npm: https://www.npmjs.com/package/postmark
- Repository: https://github.com/ActiveCampaign/postmark.js
- Homepage: http://ActiveCampaign.github.io/postmark.js
- Issues: https://github.com/ActiveCampaign/postmark.js/issues
- npm.io page: https://npm.io/package/postmark

## Recent versions

- 5.1.0 (latest) — 2026-07-10
- 5.0.0 — 2026-07-08
- 4.0.7 — 2026-02-18
- 4.0.5 — 2024-08-19
- 4.0.4 — 2024-06-20
- 4.0.3 — 2024-06-20
- 4.0.2 — 2023-12-04
- 4.0.1 — 2023-12-04
- 4.0.0 — 2023-12-04
- 3.11.0 — 2023-11-14
- 3.1.2 — 2023-11-02
- 3.1.1 — 2023-10-09
- 3.1.0 — 2023-10-09
- 3.0.20 — 2023-10-09
- 3.0.19 — 2023-07-31
- … 76 more at https://npm.io/package/postmark/versions

## README

<a href="https://postmarkapp.com">
    <img src="https://github.com/ActiveCampaign/postmark.js/raw/main/postmark.png" alt="Postmark Logo" title="Postmark" width="120" height="120" align="right">
</a>

# Postmark Node.js Library
[![Build Status](https://circleci.com/gh/ActiveCampaign/postmark.js.svg?style=shield)](https://circleci.com/gh/ActiveCampaign/postmark.js)
[![License](http://img.shields.io/badge/license-MIT-blue.svg?style=flat)](http://www.opensource.org/licenses/MIT)
[![npm version](https://badge.fury.io/js/postmark.svg)](https://badge.fury.io/js/postmark)

Send emails with the greatest of ease! [Postmark](http://www.postmarkapp.com) allows you to send your application's emails with high delivery rates, including bounce/spam processing and detailed statistics.
In addition, Postmark can parse incoming emails which are forwarded back to your application.

Now your node.js application can send emails through [Postmark](http://www.postmarkapp.com).
As the official Node.js library for Postmark, postmark.js has support for the entire REST API.

## Requirements

Minimum supported [Node](https://endoflife.date/nodejs) version `v18.0.0`. The library uses the native Fetch API and has
no runtime dependencies. If you use older Node versions for which
[active and security support ended](https://endoflife.date/nodejs), you will need to use older library versions (3.x.x for Node < 14, 4.x.x for Node < 18).

> **Note:** The global Fetch API is stable from Node 21. On Node 18–20 it works but may log an
> `ExperimentalWarning: The Fetch API is an experimental feature`. This is emitted by Node itself, not by this library.

## Proxies / custom fetch

Unlike axios, Node's built-in fetch (undici) does **not** read the `HTTP_PROXY` / `HTTPS_PROXY` / `NO_PROXY`
environment variables. If you run behind a corporate egress proxy, supply your own fetch implementation via the
`fetch` client option — for example one bound to an undici [`ProxyAgent`](https://undici.nodejs.org/#/docs/api/ProxyAgent) dispatcher:

```js
import { ServerClient } from "postmark";
import { ProxyAgent } from "undici";

const dispatcher = new ProxyAgent("http://proxy.internal:8080");

const client = new ServerClient("server-token", {
    fetch: (input, init) => fetch(input, { ...init, dispatcher }),
});
```

The same option can be used to inject a mock/instrumented fetch for testing or other transport customization.

## Usage

Please see the [wiki](https://github.com/ActiveCampaign/postmark.js/wiki) for quick start tutorial and detailed instructions about sending email at our [documentation page](https://ActiveCampaign.github.io/postmark.js/). 
For details about Postmark API in general, please check out [Postmark developer docs](https://postmarkapp.com/developer).

### Installation

Installing `postmark` javascript library is super simple. Use the following command in your terminal:

```bash
npm install postmark
```

## Migrating from older versions of the library

Please see [wiki](https://github.com/ActiveCampaign/postmark.js/wiki/Migrating-from-older-version) for more details.

## Issues & Comments

Feel free to contact us if you encounter any issues with the library or Postmark API. 
Please leave all comments, bugs, requests and issues on the Issues page.

## License

The Postmark JavaScript Library is licensed under the **MIT** license. Please refer to the [LICENSE](https://github.com/ActiveCampaign/postmark.js/blob/main/LICENSE) for more information.

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_Source: https://npm.io/package/postmark · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._