Image for post
Image for post
Photo by Holger Link on Unsplash

There are thousands of collections of any sort. Anything that you can imagine, there’s most likely someone out there that collecting it. Either puzzle, legos, posters, shoes, dresses, coins, computers, phones, anything.

Very often there’s a story behind the collection as a whole, but there’s also a story behind every piece in that collection. Sometimes a gift, sometimes related to a road trip, amongst other reasons.

When it comes to web3, it is no different. We see, very often collectibles of different types. In ethereum, one of the most known collectibles in criptokitties. But they are not the only ones. From gods unchained to blockcities and the so widely known and appreciated kudos from gitcoin, there are thousands of collectibles. …

Image for post
Image for post
Photo by Shahadat Rahman on Unsplash

It’s 3 in the morning, and you still don’t understand it. Not because it is 3 in the morning, but because someone else wrote some code in such a particular way you don’t understand it.

There’s actually a basic solution for that, called “documentation”, although I sometimes struggle with lack of it. But it’s not about documentation that this article is. It is about Abstract Syntax Tree or AST, for short.

The abstract syntax tree is a concept in computer science that represents some code in an abstract syntax form.

To better understand it, let’s consider the following line in…

Image for post
Image for post
Photo by Snehal Shah on Unsplash

After many backs and forth on decentralizing or not, you decided that you want to have a portfolio fully decentralized. Not hosted anywhere, but actually anywhere. It can even be in your printer at home, or store. Or even better, at that IoT device that you’ve put on your greenhouse. Because why not?

Too much decentralization might not be good sometimes, but this is not about being good or bad. Instead, it’s about being truly decentralized.

Going back to another article I’ve shared, it’s possible to upload a file to IPFS which will spreads over the network. This means that any file you upload will be on that first node you updated the file into. And then, when other nodes access that file, they will also download it, and have it. This prevents that anything on the internet will ever disappear as long as at least one person has it. …

Image for post
Image for post
Photo by NordWood Themes on Unsplash

Ever since we have databases, the UI always talked with it asynchronously. But we’ve never thought much about it because databases are nearly instantaneous. Thus, we just wait for the response.

This principle doesn’t always apply when talking about blockchain transactions. In small private networks with fast consensus algorithms, it’s hard to realize the time consumption. But what about large nets, where transactions take seconds? Will you ask the user to wait?

Let’s see how we can use those two different approaches.

First, waiting

Let’s start with the first and more common approaches, waiting.

Imagine you are coding a dapp, created the contracts and now ar interacting with them. …

Image for post
Image for post
Photo by Launchpresso on Unsplash

“Data is the new gold”

“Is Big Data the New Black Gold?”

“Data isn’t the next gold. It’s the next uranium”

“The world’s most valuable resource is no longer oil, but data”

Spoiler alert, I’m a blockchain developer, not a data scientist. And this article is about accessing data with TheGraph. But we are in 2019’s fall, still (or starting to) believe that data is the next gold. Although some might question it, it’s not a topic to discuss here.

Data is, without a doubt one of the best resources we’ve ever had. And not because of its monetary value (unlike gold) but because of what it tells us. Because of what it says about us. Even if it sounds uncomfortable, we sometimes find things that we didn’t know. …

Image for post
Image for post
Photo by Matthew Henry on Unsplash

“We build systems like the Wright brothers built the airplanes; build the whole thing, push it off a cliff, let it crash and start all over again.”

— R.M Graham

Well, not exactly the same, but it’s true. See, you can have a good app that does incredible things, but if it only works from the command line, then you will lose your audience.

You need a user interface (UI) for your app. It doesn’t matter if it is a mobile or browser app, you still need a UI. Looking at the current blockchain applications you and I will surely agree that we still lack some good UIs. …

Image for post
Image for post
Fans and wires on the back of a computer server — from Unsplash

If you do a lot of experiences using virtual machines and you usually break them, I’m sure you know the “oh crap, not again” feeling, just because you them have a lot of work.

What you just read is a problem. The solution? Vagrant. If you don’t know what vagrant is, have a look on the internet. But, in an easy explanation, it’s a system that has a lot of pre-installed OS, you just have to download them.

Basic Vagrantfile

To run a simple pre-installed OS with vagrant, put the following inside a file named Vagrantfile

Vagrant.configure("2") do |web01| …

Image for post
Image for post
This image have author rights :)

It’s everywhere, continuous integration is a thing and we need to understand how this works and what is it good for. To make it easy, I decided to build an ecosystem myself and now I’m sharing my experience because I think it was awesome. Bellow is the complete explanation about how to build a CI ecosystem, just like I did.



First of all, your computer is enough if it has 6GB+ RAM. Second, 10GB+ of hard drive would be awesome.


  • Virtualbox
  • Ubuntu server

First steps

I used two virtual machines so, first of all, let’s give them names. They will be called Jack and Mary. …


Bernardo Vieira

Coder, blockchain developer, writer. Why? Because I can.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store