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 also publicly available but while the public versions are licensed under copyleft licenses (AGPL, EUPL etc.) then all modules in this registry use the MIT license.

This allows you to use the copyleft version of a modules while developing your private app for free and only once ready to go public with your app get a 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.


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

The easiest way would be to download 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 into 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 private registry configuration you can install @postalsys-scoped modules like any other Node.js modules. Just make sure you are using the correct module name.

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

$ npm install -g @postalsys/imapapi

and then run normally

$ imapapi


Regular subscription plan does not include a support package. There is also no free trial, instead you can test provided packages indefinetely by installing the free copyleft licensed modules. If these modules seem to work for you then 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 to 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.
Step 4. If you want you can download an auto-generated .npmrc file for your project. This way you would not have to manually authenticate your account with the npm login command.
Step 5. Follow the instructions in the downloaded credentials file.