The Sports Extension Nobody Built: A Case Study in Finding Empty Store Categories

Most software ideas show up in our research once, get scored, and quietly fall off the list. This one wouldn’t leave. A sports extension for Microsoft Edge appeared four separate times across both of the research pipelines we run, wearing four different costumes: a new-tab companion that shows your teams’ scores when you open a tab, a live-scores extension that sits in the toolbar, a stats overlay for fantasy players, and one more variant that mashed those together. Best rank it ever hit was #2 for the week. Four independent scoring passes kept landing on the same spot on the map.

When that happens, the specific idea almost stops mattering. What matters is figuring out why the map keeps pointing there. So we dug into the numbers, and what we found is a clean worked example of a strategy you can reuse anywhere: hunting for underpopulated store categories instead of fighting in crowded ones.

The numbers that made us look twice

Here’s what the opportunity data we track says about the Sports category in the Microsoft Edge add-ons store. There are 89 extensions in the entire category. Not 8,900. Eighty-nine. The median extension there has 207 installs, which tells you most of what’s listed is hobbyist work that nobody is maintaining or marketing. And installs across the category grew 53% over the tracking period, which tells you the audience is showing up even though almost nobody is building for it.

Read those three numbers together. A category with 89 competitors and flat demand would be a dead end, a hobby shelf. A category with 53% growth and 5,000 competitors would be a bloodbath. But growing demand plus a median competitor with 207 installs means the bar for becoming the best option in the category is embarrassingly low. You don’t need to build something world-class. You need to build something that’s clearly better than a field of abandoned weekend projects, in a store where the audience is actively growing.

Why Edge, of all places

We’ll be honest: nobody dreams of building for Edge. That’s exactly the point. Every developer with a browser extension idea ships to the Chrome Web Store first, because that’s where the users are. Chrome has hundreds of thousands of extensions, and any category worth being in has dozens of well-funded, well-reviewed incumbents. Your sports extension there would be fighting ESPN’s official tooling, established fantasy add-ons, and a hundred lookalikes, all for a sliver of attention.

Edge, meanwhile, ships preinstalled on every Windows machine on earth. Hundreds of millions of people use it, many of them by default, at work, on machines where they can’t install Chrome. Those users still watch football. They still play fantasy. They open new tabs all day. And when they search the Edge add-ons store for anything sports-related, they find 89 options with a median of 207 installs. The demand didn’t disappear because the supply did. That mismatch is the whole opportunity.

There’s a second-order benefit too. Edge extensions use the same architecture as Chrome extensions. You’re not learning a new platform. In most cases you’re porting an existing manifest with minor changes, which means the marginal cost of shipping to Edge is close to zero for anyone who’s built for Chrome. The developers skipping Edge aren’t making a technical decision. They’re making a status decision, and status decisions leave money on the table.

The general strategy: hunt shelves, not ideas

Strip the sports part away and you’re left with a repeatable method. Instead of asking “what should I build?”, ask “where are the empty shelves that people are already walking past?” Every marketplace with categories publishes, or leaks, enough data to answer that: category counts, install numbers, review counts, dates of last update. You’re looking for the same three-part signature every time. Small competitor count. Weak median competitor. Growing or at least steady demand.

Edge is one hunting ground, but the pattern repeats across every second-tier marketplace we’ve looked at:

• Raycast’s extension store, where Mac power users pay for productivity tools and whole workflow categories have a handful of entries
• Setapp, which curates Mac apps and openly lists gaps it wants filled
• Firefox add-ons, GNOME extensions, and Obsidian plugins, all with paying-adjacent audiences and thin competition outside the top categories
• App stores for specific tools: Shopify’s smaller categories, Figma plugins, even Stream Deck plugins

The instinct you have to fight is the one that says a small store means a small business. Sometimes that’s true. But a mediocre extension in Chrome’s ocean gets zero installs, while a decent one on an empty Edge shelf can own its category. Owning a small category beats drowning in a big one, and small categories have a habit of growing underneath the one product that took them seriously. That 53% growth number wasn’t caused by the 89 extensions. It arrived despite them.

How the money actually works

Browser extensions monetize three ways, and you should decide before you build. Free with a paid tier works when the free version is genuinely useful and the paid tier removes friction: more teams tracked, faster refresh, historical stats for the fantasy crowd at $2 to 4 a month. One-time purchase works on stores that support it, though conversion is harder. And affiliate or sponsorship revenue works in sports specifically, because sportsbooks and fantasy platforms pay real referral money, but tread carefully there since store policies around gambling links are strict and change without warning.

Realistic math, not fantasy math: if you became the clear best option in a category where the median is 207 installs, and grew to 20,000 installs over a year on the back of category growth and near-zero competition, a 3% conversion to a $3/month tier is about $1,800 a month. That’s not a company. It’s a very good side product with maybe two weekends a month of maintenance, and it’s a foothold you can repeat across other empty categories once you’ve got the playbook down.

Who this isn’t for

If you need this to replace a salary in six months, walk away. Empty-category plays start slow because the category itself is small today; you’re betting on growth plus dominance, and dominance arrives before the growth pays. If you can’t write JavaScript or aren’t willing to learn extension basics, this specific version isn’t yours either, though the shelf-hunting method applies to no-code marketplaces too. And if you hate maintenance, skip it: sports data application programming interfaces (APIs) change, browser manifest requirements change, and an abandoned extension in a small category is exactly the weak incumbent someone else will study.

One more honest caveat. Microsoft could decide tomorrow to build sports into Edge natively, the way it bakes in shopping and news features. Platform risk on someone else’s store never goes to zero. The defense isn’t hoping; it’s keeping your build small enough that six months of revenue pays for the effort, and treating everything after that as profit.

The sports extension might not be your idea. Fine. The lesson survives the example: stop asking what to build and start asking where demand is growing while supply stays asleep. The data we track found this shelf four times. There are more shelves.