An innocent blog post on Lambda the Ultimate has generated a storm of comments about the idea of a killer app for programming languages.

I’m sure you’ve heard this expression before, and the idea is very simple: it’s an application which, in and of itself, will promote its infrastructure (the operating system, or the programming language or the framework it’s built on) from obscurity to instant fame and de facto standard overnight.

For example, one might say that Microsoft Office was Windows’ killer app. Of course, this would be simplifying the equation somewhat since a lot of factors made Windows the success it is today, but you get the idea.

While reading through these comments, I started questioning the very existence of the killer app concept. Especially for programming languages.

Let’s start with Java. Does Java have a killer app? Did Java go through the transition “obscurity -> killer app -> fame”?

Back in the early Java days (circa 1996), there was one thing that made Java stand out from other languages. It doesn’t mean that Java was more popular than these languages, nor that it was gaining momentum: it’s just that it was attached to a particular concept that was unique to it and because of that, it received a lot of hype and was discussed heavily on Usenet and other forums.

Do you remember what that killer app was?


Thanks to applets, Java was going to take over the world and redefine the web as we know it.

We all know what happened.

Applets never went anywhere, but Java had enough interesting properties that a lot of programmers started working with it in many areas, most of them never envisioned by any pundit at the time. Who would have guessed back then that Java would become the de facto standard on the back-end, sharing an equal footing with .Net in delivering millions of transactions every day to users around the world?

Let’s take another example: PHP.

Does PHP have a killer app?

None that I can think of. Of course, a lot of very successful programs and web sites are written in PHP (forums, blogs, etc…), but none of these can be considered “clinchers”. Instead, PHP became successful quietly, discreetly, behind closed doors, while both programmers and the required infrastructures (massive support by Internet Service Providers) were being slowly achieved without anyone realizing it. To onlookers, it looked as if one day we woke up, and PHP was everywhere. But make no mistake: the process was continuous, slow and developed on a massive scale.

A similar argument can be made for Javascript.

The more I thought about it, the more I started wondering if the idea of a killer app isn’t a fallacy. Or worse: a kiss of death. As soon as a programming language or a framework finds itself in need of a killer app, it has already failed and its proponents are just reaching and trying to save a product that they know is already slowly falling back into obscurity, as the rest of the world inexorably percolates toward the next big thing, one that makes them truly more productive and that doesn’t need bigot advocates to sell.

Maybe what we are really looking for is not a killer app but killer apps. Not one defining product by which all the others are measured, but a multitude of tiny ones which, individually, don’t really deserve any particular mention, but when put together, create a comfortable ecosystem in which programmers thrive, are productive and enjoy working in.

Now, let’s see if we can find the Next Big Programming Language using this criterion…