My list of side projects grew ever larger. The list of abandoned, semifinished projects did so too. That's when I decided to focus on a single side project for a longer period of time. But which one?

There are many reasons to start a side project. To learn a new technology, to build a portfolio, because you need it yourself, or maybe just for fun. All of these are fine, of course. But if you're like me, getting actual users, and a chance to monetize your project boosts your motivation and enthusiasm. Here's how to strategically pick a side project that has the potential to grow into a side income, or even create an opportunity to go full-time on what you love doing: making digital products.

The golden trio

It's not by chance that NsLookup.io made the cut. The three criteria I use to evaluate an idea are:

1. Longevity — Will it stay relevant for a long time?
2. The monetization sweet spot — Can you make a living?
3. Limited but extensible scope — Can you pull it off?

Longevity

Riding the hype train can get your project trending quickly, but you'll have nothing left when the hype is over. So find something that has longevity instead. What's something people will keep searching in the coming decades? Email, DNS, online meetings, and timezone conversions are all examples of things that have a high and steady search volume.

The monetization sweet spot

If your project can't attract any users, then it's obviously not going to generate any meaningful revenue, let along allow you to eventually build a business around it.

Too much monetization potential, on the other hand, can attract regular businesses, or venture backed businesses. So ideally, we'd be somewhere in between. Enough potential for an indie developer to make a living, but not enough for existing businesses to expand into your territory. Around €5k per month would be perfect.

A good way to gauge the amount of potential is to identify the primary search keywords, find their search volume, and analyze the top ranking websites. You'll probably find a couple of sites that are similar to your idea. That's not an issue, as long as you think you can do better in some way. Either execute better, market better, or meet search intent better. Novelty is overrated.

Limited but extensible scope

You can't undertake a massive project on the side, so the scope needs to be minimal. Once an initial version is live, it should be extensible incrementally. Adding many small features that add up to a great product. Since side projects are mostly done in the evenings and weekends, the available time is usually chunked in sessions of a couple of hours. That's another reason to find something that can be built iteratively. Try to ship something every other session.

For NsLookup, this meant launching with a single page, and adding features and content along the way. Now that I've gone full-time, I can invest more in quality and bigger features, but it was good to start with a limited but extensible scope.

And that's how I picked NsLookup as my main side project. It has longevity, is in the monetization sweet spot, and has a limited but extensible scope. If you're interested in growing a side project into a business, then you should follow me on Twitter, where I share what I'm learning while working full-time on NsLookup.