Based on the projects I’ve engineered throughout the years the choice was quite obvious but it needed to check this boxes:

• Experience
• Large community
• OSS
• Cheap

The selected technologies responded to all the above requirements. For more details we’ve shared our complete stack here.

Development Tools & Services

Choosing Ruby (RubyOnRails) over Go was a challenge due to the fact that I I’ve been developing my own set of tools (avoiding to call it a framework, but definitely going to need to find some time to make it ready for a proper OSS project) for Go but RubyOnRails was the winning factor. It’s mature, fast (yeah, it’s faster to deliver products than it’s with Go) and I’m very experienced with it also.

For the presentations layer we had the classic fight between Flutter vs. React but actually the choice was much easier here, flutter all day. Based on the fact both platforms matched very well in regard of features, support and maturity the only differentiators where just the experience I had with it and the developers pool available in country. For the simple pages for Wiza VueJS was the option no competition here.

The choosing of a message queue was also a simple deduction based assertion based on the fact of being a battle tested solution and also because of having a very substantial experience with it. Ruby On Rails has very solid messaging queues “solutions”, but I wanted to make sure if I needed to change the backend in the future it will be possible without changing the whole chain. So, RabbitMQ was the solution as it delivered everything we wanted:

• Scale to large monolith or microservices
• Use of multiple message queues solutions
• High availability
• Simple decoupling

As the image above suggests, we needed a object storage solution and you could hear the drums of Microsoft Azure and AWS in the horizon… but of course I would not go for it just for the simple fact that we did not have the financial resources to burry uncontrolled thirsty of storing at these services. We went for Minio a similar service that was compatible with S3 cloud storage service. We could handle the service management, it could give us the tier one level service and we could decouple later (which would imply that we are able to afford it). So, team experience, large community and OSS boxes are all checked under these technologies.

So… who’s hosting that baby ?

Well, we clearly did not have much of financial room to maneuver to get saved by the magic of push and deploy, but we had the boldness and the ninja skills and also it was 2022 not 1999, Ubuntu VPS + docker + kubernetes equals let’s Go!!!

So, I spun a couple of virtual private servers on AWS and Azure and got my hands “dirty” on building a multi regional cluster for everything. Setup a backend services running RubyOnRails API services pods, NGINX fired up and run as Web Server and Reverse Proxy for everything accessible outside and AWS bouncing connections with Amazon ELB.

We spin our own container registry just because we wanted to make sure deployments were faster and cheaper of course with the maestro Kubernetes handling the orchestration using MicroK8s with Github Actions.

Keeping an eye on everything

When talking about other people money the first thing that comes to my mind is Big Worm quote about handling other peoples money “…Playing with my money is like playing with my emotions” and to maintain a tip top service on a financial business without playing with others emotions it’s necessary top notch solutions to monitor closely everything that happens in and around the platform. Papertrail (SaaS) comes to rescue as solution to log everything from backend services which then shovels them to Loki which we run it as a private container service. Then Grafana centralizes all the monitoring for every single service and server running for the platform.

Decisions are based on data

We try to relay on data as much as we can, and to give the glimpse over what happens at Wiza we had to implement a solution that could give the freedom to collect and analyze data without much technical expertise or effort. So, Apache Superset delivered plethora of options, more than we needed at start and being a OSS made it even more attractive.

The skills to build, deploy and maintain all those tools and services together spans over multiple disciplines and can only be achieved with several years of experience in several areas, I recognize that. But the most significant skill is the ability to incrementally putting them together at the right time, this requires methodology and luckily software engineering has some very interesting ones and I look forward to share next time how we’ve managed to put some of them together to continue to deliver products and features to Wiza in my next post, until them “Wiza tukina”

By 2022, I was finishing up an assignment and just left a partnership (vPOS) I was involved  with and I wanted to do something different within fintech. I received multiple invitations to lead engineering teams in a couple of fintechs but I passed on the option simply because I was not too attracted to the direction some where going or because I just could not understand their vision, but I did consult for some of them for a while.

During this whole time I started to work on something that I later shared with one of my old partners and based on the experience we had within the Angolan market it just made sense to try it. So, myself and Kamal D’Nigel decided to take this on and create what is today known as  Wiza, and so far it has been a good experience.

The image below shows what life was like for me in 2022, working almost everyday. I lived by the motto of “Work smarter” but this new venture required me to “Work harder”, whilst Kamal was out there trying to convince partners and merchants that this was the way forward. If you ever tried to do anything in Angola you should put some respect on the work that he was putting in.

By year 2023 the scenario did not change much for me, at least for the first semester, and you can imagine how this affected me personally and professionally. I had to literally coded almost everyday and had to handle other business responsibilities that I had at NEXT.

By the last semester of 2023 most of the payment providers were on board in Angola, including one in RDC (Republic Democratic of Congo) and we had on board a couple of customers using our platform to facilitate payments and manage their business operations. During this time I was able to bring on board two developers to help me on mobile development and frontend development.

Myself and Kamal were on full time support mode. Guaranteeing the clients satisfaction became the number one task, I even joined WhatsApp (those who know me understand what that means). Today in 2024 the platform has matured in processing thousands of transactions per day but more importantly there are small, median and even larger business who relay 100% on Wiza for their business management, payment processing, e-commerce and others.

Now that we reached that moment where Wiza has seen enough battles to go general public, we are going to be releasing these solutions one by one for small business owners and large corporations with business models that make sense for all. I’ll be telling you all about the technology choices and the challenges I faced so far and what methodology I’ve been using to handle them in future posts.

With the recent developments in terms of social gatherings aka social networks the one that has caught my attention if the bluesky project with his new protocol and features such as moderation I believe I can once more try and give this thing one more ride.

This is it for now and talk to you until next post.

PS: I’ve sign-up to bluesky and you can find me at @sergio.ao