Postal Systems private registry is a registry for email-related Node.js modules from the authors of the Nodemailer project and other similar projects. All these modules are publicly available, but while the public versions are licensed under copyleft licenses (AGPL, EUPL etc.), all modules in this registry use the MIT license.

This allows you to use the copyleft version of a module while developing your private app for free. Once ready to go public with your app get a Postal Systems private registry subscription to install the MIT licensed modules. There is no other difference between public and private modules besides module names (private modules are prefixed with the @postalsys-scope) and license terms.


Applications built by Postal Systems require a license key to unlock all features. You can provision those licenses in the License Keys section. Once you have generated the license key, you can download it and upload or paste it to the license key field in the application you want to use.

Private Registry Setup

This section only applies if you want to install private modules. If you use applications with license keys, then you do not have to go through this setup.

First, you'd set up NPM to use Postal Systems private registry for all @postalsys-scoped modules.

The easiest way would be to download the credentials file from the Registry credentials page, rename the downloaded file as ".npmrc" and store it into your project's root folder.

If you want to set up Postal Systems private registry for your entire account, not just a single project, you can do it with the following npm commands.

These steps need to be run just once as authentication and scope info are stored permanently in the account's .npmrc file.

1. Route requests for @postalsys-scoped modules to Postal Systems private registry.
$ npm set @postalsys:registry
2. Authenticate against Postal Systems private registry using the generated credentials.
$ npm adduser --registry= --scope=@postalsys

Using private modules

If you have set up the private registry configuration, you can install @postalsys-scoped modules like any other Node.js module. Just make sure you are using the correct module name.

For example, to install the mailauth command, run the following command.

$ npm install -g @postalsys/mailauth

and then run normally

$ mailauth


A regular subscription plan does not include a support package. There is also no free trial; instead, you can test provided packages indefinitely by installing the free copyleft licensed modules. If these modules seem to work for you, upgrade to a paid plan for the MIT licensed versions.

For bugs, you can file tickets in the Github repositories for the copyleft licensed modules. All fixes also get copied into the MIT licensed versions.

If you do need support, then sign up for the Support plan.

Creating credentials

Step 1. Click on the "Create new credentials" button.
Step 2. Provide a descriptive name and click on "Create credentials" button.
Step 3. You can view the password by clicking on then eye icon.