Paubox is excited to offer on-demand SMTP access to our Paubox Email API customers with zero configuration required at the customer domain level. This service extends the flexibility of the Paubox Email API so you can use SMTP with any number of third-party tools and ensure that you are sending email using Paubox’s HITRUST CSF-certified email encryption.

As an example, let’s say you are not currently using Paubox Email Suite so your SMTP services are not configured to provide comprehensive outbound encryption. However, you have a subset of messages that does require encryption -- messages sent from Auth0 or some other software service, for example.

This scenario makes you a prime candidate for using the Paubox SMTP API.

As a Paubox Email API customer you can easily set yourself up to use SMTP when necessary using the instructions below:


There are two simple requirements to successfully use the Paubox SMTP API:

  1. Emails must be sent from an address on the domain associated with your Paubox Email API Key.
  2. You must use Login authentication over TLS for SMTP.


If your use case satisfies the above requirements, you can get setup with the Paubox SMTP API by following the first three steps in our Paubox Email API Quickstart Guide as summarized below:

  1. Sign-up for the Paubox Email API Service
  2. Activate and verify your domain.
  3. Generate a Paubox Email API key.

Once you have an API key, you can use the following details to configure SMTP for whatever service you are using.

SMTP Host:

SMTP Port: 587

SMTP Username: apikey (Username is “apikey” for all Paubox customers)

SMTP Password: Your Paubox Email API key generated in Step 3

IMPORTANT REMINDER: You must send your email messages with a “From” address that matches the domain associated with this API Key.

Real World Example

If you are setting up Auth0 to use the Paubox SMTP API your settings would be as follows:

Example SMTP2API connection

Once configured properly, any email messages generated from Auth0 will be sent through the Paubox SMTP API.

Bonus Features

Aside from gaining the peace of mind that you’re sending using Paubox’s HITRUST CSF-certified email encryption, you will also gain access to the following features:

  • Summary Usage Statistics
  • Detailed Log Interface
  • Log Searching
  • Webhooks Access

For additional support, please contact or visit the Paubox Support website.