Announcing vSMTP AI

Two years ago, when we started thinking about version 3 of vSMTP, one of our main areas of thought was to reduce manual maintenance operations to favor automated actions as much as possible.

The first step was to enable users to interact with vSMTP behavior on the fly and be able to write complex scenarios to interface with their systems.

I am proud to announce that the second stage is underway: gradually delegating basic functions to artificial intelligence: vSMTP now includes a library made up of AI routines capable of interacting with email flows on the fly.

An example: bounces and transients

Categorizing bounced and transient emails is crucial for your business to maintain a positive sender reputation with service providers and thus meet your customer service level agreements.

For years, the solutions used were limited to an obscure jumble of lists of regular expressions, allowing empirical categorization of DSNs trying to catch sentences like:

*) 550 5.0.0 zzmail services - this mailbox is full. Please retry later.
*) 552 5.2.2 foomail - the end user's mailbox quota has been exceeded. Please retryCode language: Markdown (markdown)

I’m not even talking about the case where the service provider decides to change a word like “mailbox” to “mail box”…

Even now, our competitors are announcing new features like “custom categories” or “arbitrary bounce classification labels”. We do know that users must have the flexibility to define their own categories to refine their processing and meet their own requirements.

However, heavy use of REGEX lists is definitely an old-fashioned processing method.

This is why we have developed an AI routine specifically for bounces categories.

Natural Language Processing

vSMTP automatically detect and categorize bounced or transient emails using a neural network specialized in natural language recognition (NLP).

What is natural language processing? let’s ask the one who democratized its use, ChatGPT: […]Natural language processing (NLP) is a field of artificial intelligence that focuses on the interaction between computers and human language, allowing machines to understand, interpret, and generate human-like text. This involves developing algorithms and models to extract meaning, sentiment, and context from natural language data[…]

Extracting meaning, sentiment and context… That’s exactly what we need. You should consider the DSN reasons for a bounce message as a review of a movie and the category searched for the sentiment/review of the movie, rated from 1 to 5.


After an initial learning period, the SMTP engine no longer works with regex or patterns but instead analyzes and infers the meaning of the DSN status. Periodically, the neural network updates itself. This contributes to smoother and more reliable email handling. Notable benefits are:

Reduce the work devoted to maintenance: instead of dealing with endless lists of REGEX, the user can focus on much more valuable work.

Simplify the classification process: instead of managing endless lists of REGEX, the AI can intelligently categorize reasons based on natural language understanding, which is particularly valuable when dealing with variations in language use.

Eliminate emergency fixes: updates from service providers are no longer considered as breaking changes. By leveraging AI, vSMTP adapts to changes in message language or structure without requiring manual intervention.

The better the tools, the better the business

This is an example among others of the power of vSMTP artificial intelligence subroutines.

If you would like to learn more about the multiple capabilities of vSMTP and how it addresses other challenges in email processing, please do not hesitate to contact us.

Stay tuned.

Designed for cloud computing

There was not much movement happening in vSMTP for a few months, as we were working behind the scenes on the third version of vSMTP with a completely new architecture.

We rebuilt the server from the ground up, moving from a monolithic architecture to a micro-service architecture, using AMQP as the main way of communication between services.

A new architecture

Since then we did great optimizations, the transition to a micro-service architecture was the major shift in how vSMTP version 3 is structured. This change involved breaking down the server into smaller, more manageable services, each responsible for specific functions.

The micro-service architecture offers benefits such as scalability, flexibility, and easier maintenance.

RabbitMQ and AMQP

Using AMQP (Advanced Message Queuing Protocol) and RabbitMQ as vSMTP messaging infrastructure was an obvious choice.

RabbitMQ acts as a message broker, facilitating the exchange of messages between different vSMTP services. It provides features such as message queuing, routing, and load balancing, which improve the reliability and scalability of vSMTP.

Microservices, AMQP and cloud computing

Microservices architecture and the use of Advanced Message Queuing Protocol are well suited to cloud computing for several reasons, as they align with the key principles and benefits of cloud-based applications:

  • Scalability and elasticity
  • Resource allocation and efficiency
  • High availability and fault tolerance
  • Global reach

In summary, microservices architecture and cloud computing naturally complement each other due to the alignment of their fundamental principles and capabilities.

The combination of vSMTP’s new internal architecture with the scalability, flexibility, and managed services of cloud platforms enables messaging service providers to build and operate modern, resilient, and efficient infrastructures that can meet the demands today’s dynamic and evolving business environments.

You can right now download the release candidate on GitHub. Our teams will be happy to guide you during your installation.

Stay tuned. Join us on Discord, X and LinkedIn.