Global Online Fraud Losses = 140,000 Jobs

By fcolas

The growth of global losses due to online fraud over the past 10 years (Ubivar)

Over the past 10 years, the volume of global fraud losses for online payments has increased at an average rate of 10% each year. As of 2014, the global losses due to fraud are expected to reach the astounding amount of $14bn, which is equivalent of 140,000 jobs.

In what follows, we first describe the two factors that explain the exponential growth of online fraud over the past ten years, and then we review the fraud losses faced by an average US company, hypothesising on the factors that increase and that decrease fraud rates for companies.

1. Why Do Global Fraud Losses …read more

Source: Ubivar Risk Analytics


Seven Players in Online Payment Processing

By fcolas

Online Payment Processing

Nowadays online payment processing is so efficient that we never question how it works behind the scene. We go to Amazon and we buy best-selling books, trendy clothes, and even fresh food. Or we go to Expedia and we order an airline ticket worth $1,000. We receive an email confirmation that says that the ticket is issued, but nothing else.

In what follows, we will review the business entities that make online payment processing possible. It starts with the merchant website, and it continues with payment gateways and payment processors. It involves credit card unions and it involves three …read more

Source: Ubivar Risk Analytics

The sales funnel process, its seven states, its engineering, and its recent changes

Seven states of the sales funnel

Seven states of the sales funnel

In this post I review the sales funnel process, its engineering and its recent changes. The sales funnel is the term used to describe the selection process that occurs when converting potential customers into buyers. At any time a potential customer who enters the sales funnel is in one of three states. It is a lead, a prospect, or a buyer.

To become a lead a potential customer has to enter in our ‘radar’. To become a prospect a lead needs to be aware of our product. And to become a buyer a prospect has to realise a purchase.

The two objectives when optimising the sales funnel process

There are two objectives when optimising the sales funnel process.

  1. First we want to maximise the number of leads.
  2. Second we want to maximise conversion rates. From leads to prospect. And from prospects to buyers. Continue reading

Integration of in’s Website

Context. Recently I worked at, a social network for construction companies that use the platform as a means to bid for construction packages and to exchange between contractors and sub-contractors; as of May 2014, the user base starts expanding beyond California’s boundaries with more than 2,000 users. In need of support to develop new functionalities and to go with the growth of the platform, Jesse Pedersen, CTO of, reached out to Hack Reactor three weeks ago.

Contribution. Together with Farid Siddiqi, Tristan Yu, and Jonathan Tewksbury, I spent the last two weeks at BuildingConnected. Among other things Farid, Tristan and Jon worked on caching results to avoid network round trips (backend), on translating wireframes into views (front-end), on improving user experience (front-end), and on a note-taking functionality; I focused on the full integration of, a cloud storage service.
My three take aways are that box works from end to end, that the dev was back-end-heavy with a lot of async waterfalls and authentication stuff, and that it involved a good deal of redesign. Continue reading

Making of, an Angular Google maps web-app

In this post I do the making of, an Angular Google maps web-app collecting 150,000+ free food and drink events in Bay area, which I co-developed with Rob Graeber and Abdelatif Sebbane as part of Hack Reactor. First I come back on our tech stack, on the why of Angular Google maps, and on our top-5 features. Second I review the how to of Angular Google maps. And finally I wrap up with the main challenges faced when developing the front-end.

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Why I Joined Hack Reactor as an Academics, a Review


In this post I review the reasons that lead me to Hack Reactor from an academic background. First I resume both my past eight years as an academic and how I got rid of the so-called impostor syndrome. Second I summary the take home of research, my move to industry, and ‘change’. Finally I conclude why joining Hack Reactor has been an experience beyond all my expectations.

Eight years in research, and the end of the impostor syndrome

Ten years ago, after my electrical engineering studies I started a phd because this was my dream. Then I landed an awesome postdoc at UCLA. This was another of my dreams too. Then I did a postdoc in statistical genetics that allowed me to lift up my mathematical skills and to rejoin my long time interest for modelling. Finally, I pitched my postdoc to an Harvard colleague’s research group.

That’s exactly when I understood that I was no impostor. That’s exactly when I got the confidence that I could tackle top-grade analytics problems. That’s exactly when I started to fly on my own…

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[Press Release] New App, takes free food to the next level

1400094487843A group of students at engineering bootcamp, Hack Reactor, have released,  a new app that lets you find free food from nearby events in your area.

Designed for the starving college student, let’s anyone find free food instantly by just entering your current location and available time. Corporate sponsored parties? Got it. Art gallery openings? Yep. Free promo events? Of course. Score free food while connecting with your local community. pulls in local events from sites like Meetup, Eventbrite, and more. Then filters it based on your personal interests (and food preferences). If free food isn’t your thing, search for quick food choices ranging from food trucks to happy hours.

Simply head over to to get started.

An unexpected perspective on complexity from the Fibonacci series

Aloe Vera illustrating the fibonacci series

Aloe Vera illustrating the fibonacci series

Sun Flower also illustrating the Fibonacci series

Sun Flower also illustrating the Fibonacci series

In this post I come back on an unexpected perspective on complexity from the Fibonacci series. First I recall who Fibonacci is, and what the Fibonacci series is. Second I review the algorithmic complexity of a top-down recursive calculation of the Fibonacci series. And third I present the benefit of reversing the problem, and of solving it from the bottom up.

Fibonacci, the mathematician and the series

Fibonacci was an Italian mathematician who was considered by some as one of the most talented western mathematician of the Middle Ages. In his 1202 composition Liber Abaci” (Book of Calculation), Fibonacci contributed to the spreading of the Hindu–Arabic numeral system in Europe. In his book he gave an example of a series of numbers which is nowadays named after him. This sequence of numbers follows the recurrence relation:

F(n) = F(n-1) + F(n-2), given
F(0) = 0 and F(1) = 1.

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Bottom-up recursive n queens misses solutions

In this post I come back on an unexpected finding when working on a toy algorithmic problem, bottom-up recursive n queens misses solutions. So in the following, first I reformulate the n queens problem. Second I describe a recursive n queens. And third I describe the new, permutation-based, non-recursive solution, and why recursive n queens failed.

The n queens & n rooks problems

At Hack Reactor, one of the assignments we receive is to design a solver for the N-Queens, a problem which aims to place N-Queens on an N×N chessboard so that no two queens attack each other. Initially, we look for an algorithm finding a solution for any chessboard size but then we also want to find all solutions and return how many there are. Yet, to begin with and as a warm up exercise, we start solving the less constrained N-Rooks problem (N-Queens’ close-cousin) which aims to find the ways of placing N non-attacking rooks on an NxN chessboard.

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Software scale up: why it matters, what we aim for, and an how to

software scale up

Software scale up, Thumbnail

In what follows I explore software scale up: why it matters, what we aim for, and an how to. First I set the context of software scale up. Of how come it is a topic of interest for me now. And of the general programming concepts that are used to support software scale up. Second I set the two objectives that we are after when aiming for software scale up. And third I explore the how to of making (web) software scale up.

Why does software scale up matters?

Speaking of software practices that do not scale, we often qualify as “spaghetti code” some twisted and tangled code that makes direct functional calls to multiple parts of a software application. Likewise, we also refer to “dependency hell” a situation where an application requires numerous libraries that are version-specific and that may conflict with each other.

As I attend Hack Reactor in San Francisco, I have yet another opportunity to come back to the fundamentals of computer science and notably to algorithmic complexity and the Model View Controller software pattern (MVC). In fact, as I relate these two computer science aspects with my experience in research and industry, I (so!) fully understand how the sustainability of a software application depends upon design choices that I wanted to extend the topic a little further through this blog post. Continue reading