[ The code for this blog post can be found here: https://github.com/gustavoguimaraes/smart-contract-testing-javascript-example-] Smart contract developers strive to mitigate bugs in their code as they can be literally costly. For this end, one of the techniques we use is to write tests extensively or dare I say obsessively to the codebase. …

There comes a time when one wonders the meaning behind certain features in the programming language one enjoys coding with. Lukas Cremer, Gerard and I are blockchain developers based in Berlin, Germany, and we challenged ourselves whether we could explain the use of solidity’s using keyword. using is used for…

I just returned from the Pillar Unconference in Poprad, Slovakia where I gave two talks on developing smart contracts. The disclaimer here is that Pillar have just had a successful Initial Coin Offering and I helped writing the code for the token and crowd sale smart contract. One of my talks was on creating your first smart contract. Here is the recorded live broadcast of the talk. Unfortunately, it was difficult for web viewers to see the code of this presentation. For this, I am going to leave the code here so you can follow n case you have watched or will watch the video.

I have been going through functions in smart contracts code I am creating and decided to make it more explicit as per this best practice . I noticed that I hesitated whenever I was about to add either the public or external visibility mark. This came from a place of…

The effect of having a market cap north of $10 Billion USD is that a growing number of blockchain enthusiasts trust putting their Ether only in smart contracts that have been vouched and fine-combed by security professionals. Among the emerging best practices, the most recommended are to write extensive unit…

Tools of trade and Guidelines — Blockchain applications may impact the way that individuals and organizations interact. For this to happen, we need way more people developing these applications and for this they need to learn about creating smart contracts which are in a way blockchain powered apps. This blog post is a brief overview of…

To code smart contracts is certainly not a free picnic. A bug introduced in the code costs money and most likely not only your money but also other people’s as well. …

Update: this blog post has been updated for OpenZeppelin Solidity version v2.0 I have tested this blog post with the following dependencies: - node@10.11.0 - truffle@v4.1.14 - ganache-cli@v6.1.8 - zeppelin-solidity@2.0.0 Token contracts are hot. Token crowd sales aka Initial Coin Offers(ICO) are hotter. There have been a lot going in…

On my last post I went through the steps to deploy the smart contracts the hard way on one’s own Ethereum private blockchain. This one I am going to show the straightforwardness of doing so with Truffle, the de-facto framework to publish smart contracts on Ethereum. Let’s start by installing…