Will Stellar Lumens be the next cryptocurrency star?

The cryptocurrency hype is on. And it does not signal to slow down anytime soon. While Bitcoin is the first and by far the most popular digital currency the landscape in 2021 offers a lot more.

In this post I am comparing Bitcoins (BTC) with Stellar Lumens (XLM), the native digital currency of the Stellar protocol. Stellar’s mission is to setup an open and distributed digital payment infrastructure that can scale globally, supporting various currencies and avoiding high unnecessary fees.

Screenshot from Stellar Beat Dashboard (Stellar network visibility)
Screenshot from Stellar Beat Dashboard (Stellar network visibility)
Screenshot from stellarbeat.io

The Concept

Bitcoin in 2009 was “forged” without any other model to compare to. The initial view was to offer a secure…

Load balancing microservices and wildcard SSL certificate

This post will show how to configure NGINX as a reverse proxy with SSL support, then how (and why) I have migrated to Traefik.

Logos of technology described in the blog post
Logos of technology described in the blog post
Image by author

The article has four sections:

  • Introduction of the project where the migration took place
  • Deployment with NGINX and Certbot
  • Moving to Traefik and its benefits
  • Configuring Traefik with a wildcard SSL certificate


NGINX is an extremely popular Web Server: it is fast, free and simple to start with. It was my immediate choice when developing one of my personal projects:

CryptoLastMinute provides a detailed view of the price changes in the last 60 minutes for 500+…

Tutorial and a real example: the “World Capitals” Chatbot Quiz

Screenshot of the World Capitals Quiz chatbot
Screenshot of the World Capitals Quiz chatbot
Image by author

One of the features that make Telegram a great Chatbot platform is the ability to create Polls. This was introduced in 2019, later improved by adding the Quiz mode and, most importantly, by making it available to the Telegram Chatbot API.

It is possible to create a Poll directly in the Telegram application (without coding) but here we will explore how to develop from scratch a Telegram Chatbot quiz using the Python Telegram Bot library.

First some warming up: play with a live example and test your knowledge of the world’s capitals 😎. …

Farewell (and thank you) to DependaBot Preview

On Apr 29th, 2021 the amazing Dependabot (Preview) shut its doors: all existing customers and repositories are going to be migrated onto the GitHub-Native Dependabot, seamlessly integrated with the whole GitHub platform.

Let’s explore differences and what is useful to know.

GitHub and Dependabot logos
GitHub and Dependabot logos
Image from GitHub blog

Dependabot Preview

Dependabot is one of the most useful and valuable tools for software development: thousands of companies, communities, and repositories have been kept safe against vulnerabilities in the upstream (open source) dependencies since the tool started featuring on GitHub Market place in 2019. …

A close look at maximum supply, price and how to buy it

In the crowded jungle of Altcoins it is hard to keep up. New coins and new concepts popping up every day, hordes of enthusiastic investors dreaming of their exit strategy, spectacular price trends that make all of a sudden a cryptocurrency famous and wanted.

It is a fascinating outlook where competition is fierce and the logic of the market is unpredictable, just look at the success of Dogecoin (DOGE), a currency based on a popular Internet meme.

But there is one which seems special because of its name and a very low value: the FREE Coin.

FREE Coin logo
FREE Coin logo
FREE Coin logo


The FREE Coin is…

The most frequent errors and how to address them.

The deployment of Java applications on Heroku is pretty simple: there are different options (with git, Docker Registry, Heroku Maven plugin), lots of documentation and examples.

Unfortunately it does not always run smoothly and developers need to understand what error codes mean and what can be done about it.

Java books in a bookcase
Java books in a bookcase
Photo by NeONBRAND on Unsplash

Error R10: Web process failed to bind to $PORT within 60 seconds of launch

Java (web) applications that serve HTTP requests are deployed on a Web Dyno and must bind to the dynamicPORT assigned by Heroku. This port is mapped to a custom herokuapp HTTPS url (ie https://{appname}.herokuapp.com) .

A frequent mistake is hardcoding (ie 80 or 8080 ) the port number or leaving it…

Descubre funciones avanzadas que pueden ayudar a que tu chatbot marque la diferencia.

Photo by Christian Wiediger on Unsplash

Telegram es una plataforma popular para desarrollar chatbots: excelente documentación, comunidad activa, varias bibliotecas y toneladas de ejemplos.

Si estás comenzando, hay muchos tutoriales, especialmente en Medium. Y Stackoverflow también es un gran recurso para responder preguntas y comprender problemas (a menudo el autor está disponible en ese canal para intentar ayudar a otros desarrolladores 🤓).

En cambio, este artículo se centra en aspectos más avanzados relacionados con la implementación de un bot de Telegram usando Python Telegram Bot:

  • Pull vs Webhook.
  • Coge el ID de chat.
  • Muestra “Escribiendo …” y sugiere respuestas.
  • Deep linking.
  • Envía medios y archivos.

Modo de sondeo para trabajar localmente


Options to overcome the Heroku ephemeral filesystem. For free.

The Challenge

Heroku file system is ephemeral: applications can write on the file system but any change is discarded when the Dyno (the application host) restarts, making this option only suitable for temporary data.

It is also important to remember that Heroku implements cycling: every Dyno reboots (at least) every 24 hours and all local filesystem modifications are deleted.

A solution

Applications that must persist data should instead rely on an external database or a remote file server. …

Build Intel64-compatible Docker images from Mac M1

Docker Desktop (natively) and Heroku CLI (with Rosetta) work nicely on the Apple M1 processor, however, a locally built Docker image will not successfully deploy onto the Heroku Docker Registry.

In a previous article Deploy to Heroku From a MacBook M1: Heroku CLI or GitHubActions, I have described how it is possible (and very convenient) to build a Docker image and deploy it to Heroku using GitHub Actions. Here I am going to look at how to, in a Mac development environment, build and release an image that is compatible with the Heroku Docker Registry runtime.

Image by author

What is happening?

Building and deploying Docker…

Discover advanced features that can make a difference

Telegram is a popular platform to develop chatbots: excellent documentation, vibrant community, various libraries and tons of examples.

If you are getting started there are plenty of tutorials around, especially on Medium. And Stackoverflow is also a great resource for answering questions and understanding issues (your author is often spotted there to try helping fellow developers out 🤓).

This article instead focusses on more advanced aspects related to the implementation of a Telegram bot using Python Telegram Bot:

  • Pull vs Webhook
  • Grab the chat ID
  • Display “Typing…” and suggest answers
  • Deep linking
  • Send media and files
Photo by Christian Wiediger on Unsplash

Polling mode to work locally

Telegram Bot can work…

Beppe Catanese

My stories and projects about Software Engineering, Data Engineering, Chatbots and Crypto

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