The Accidental Entrepreneur: How a Forgotten Side Project Amassed 100,000+ Users
For years, Denis, a front-end engineer at Uber, had completely forgotten about a small browser extension he’d built on a dare. By the time he checked on it again, it had quietly amassed thousands of loyal users. That forgotten side project, Clipboard History Pro, would eventually grow to over 100,000 users and lead to a successful acquisition by Third South Capital in 2023.
In an interview with Third South’s Colin Burns and Myles Marino, Denis shares the pivotal moments of his journey: from the 'fail fast' philosophy that guides his work, to the user feedback that scaled his business, and the hard-won lessons that every indie developer can learn from.
Clipboard History Pro: By the Numbers
- Origin: 2013, as a personal experiment.
- Currently: 135,000+ installs across Chrome and Edge.
- Acquired: 2023 by Third South Capital via Acquire.com.
To start, could you give us a bit of information on your background and how you got to where you are today?
Denis: I'm a professional software engineer with about 13 years of experience, mostly in front-end development, but I also handle back-end work when needed. Currently, I'm a front-end engineer at Uber, where I've been for five years. My passion for building things is how I learned this profession. I'm a self-taught engineer, and I was earning my first money from building things years before I studied engineering in university. I think I made my first $100 in the seventh grade selling unique ICQ numbers and email addresses on a small e-commerce site I built.
From there, I moved into HTML and CSS, which was challenging with Internet Explorer 6. I learned jQuery, then JavaScript, which is a common path for many who learned back then…framework before the language. I also worked with PHP and WordPress. Now, my standard stack is React, NodeJS, and TypeScript.
I truly love what I do; it's both my career and my hobby. I often say I close my work IDE and open my personal one. For me, a good evening is spent working on a new project, trying a new technology, or just building something new.
Clipboard History Pro was one of those side projects. What are some of the other projects you’ve worked on?
Denis: One of my first successful projects was a website that scanned local computer ports. My friends and I used to play Counter-Strike, and we needed a way to check if our local server ports were open for others to connect. The website I built did just that. It eventually evolved into a more general network tool that could check various ports and protocols and perform 'whois' lookups. This was around 2009. I put some ads on it, and it started bringing in a few dollars a week. For a kid not yet out of school, having a $25 a week budget was a huge deal.
"I realized I had an audience, and if you have an audience, you can build a business."
More recently, after selling Clipboard History, I collaborated with another engineer on a browser extension called TrackerJam to help people analyze how they spend their time in the browser.
We built it out over a year, and it even became 'Product of the Day' on Product Hunt. We got hundreds of new users, but very few converted to paying customers after the free trial. We realized that many companies wanted to own their data, which presented a significant technical and contractual challenge for a side project. My partner and I felt a bit burned out, and I realized I wasn't a user of the product myself, which made it hard for me to contribute meaningful feature ideas. We decided to sell the project, basically covering our costs for freelancers and legal documents. It was a very positive learning experience, especially on the technical side, but it taught me a lot about the importance of product-market fit and having a deep understanding of the problem you're solving.
Another project is Sketch2Scheme, which I created over a weekend to play with the OpenAI API. I released it quickly with minimal marketing, just a Product Hunt submission and a few listings in app catalogs. It now brings in about $200 a month with no active work from me. It just goes to show that sometimes the projects you spend the least amount of time on can find their own success.
You’re quite prolific when it comes to creating new products. What’s your philosophy for deciding whether to continue with a new project?
Denis: I've discovered there are two main schools of thought. The first is to stay consistent, work on a project for years, and eventually find success. The other is to "try fast, fail faster." I prefer the second approach now. I aim to build and release something in a month or two. If it gets users and I’m personally excited about it, great. If not, I move on. The experience with TrackerJam, which we worked on for a year, contrasts with Sketch2Scheme, which I built over a weekend and now generates passive income. This has shown me that quick iteration and moving on from projects that don't gain traction is often a better strategy.
What was the origin story of Clipboard History Pro? Was it a “fail fast” situation that just took off?
Denis: It started as an experiment around 2013, during the early days of browser extensions. Clipboard managers have been around since the 90s, but a friend challenged me to build one as a browser extension. I was new to the browser extension API, and it was one of my first published extensions. I built it quickly for my own needs, published it, and then completely forgot about it for a few years. When I checked back, it had thousands of users. I think around 9,000 weekly active users according to the Chrome Web Store. I was shocked. I started reading the comments and feedback and began iterating on the extension based on what users were asking for. For the next few years, I continued to build it as a completely free tool.
When did you realize Clipboard History Pro could become a real business?
Denis: I think it was when the user base hit around 50,000. I created a poll using Google Forms to ask users what features they used, what they liked, and what they didn't. I put a small link to the poll in the extension's popup. In just a week, I received nearly a thousand replies. That was a huge moment. I realized I had direct access to my users and could reach them. Thousands of replies in a week is significant.
It showed me that I had an audience, and if you have an audience, you can build a business. I started integrating Google Analytics to understand user actions better, but the direct feedback from emails and the Chrome Web Store comments was the most valuable. I made it a point to reply to all free users within 48 hours to keep that feedback loop going.
What factors led to your decision to sell the company?
Denis: There were three key factors. First, after working on the same side project for years, I wanted to try something new and didn't have the time to pursue other ideas.
Second, Google announced the migration from Manifest V2 to V3 for Chrome extensions. This was a major technical update to the Chrome Extension platform, requiring many developers to rewrite their extensions. The timeline and technical requirements were unclear at the time, and I knew it would require a significant amount of work to migrate. It highlighted the risks of building on a single platform. We've all seen how quickly things can change, like when Apple made flashlight and QR code reader apps obsolete by building them into the OS. Relying on one platform for a full-time business can be risky.
[Editor's Note: Manifest V3 was a significant technical update to the Chrome Extension platform, requiring many developers to rewrite their extensions to maintain functionality and security.]
Finally, user support was starting to take up more and more of my time. I realized I was at a point where I either needed to go full-time on the project, which wasn't feasible for me personally, or let it go. I hesitated for a few months, but ultimately, I wanted to challenge myself to build something new and not be known as the guy who only built one successful thing.
Despite the risks, are there advantages to building on a platform like the Chrome Web Store?
Denis: Absolutely. Despite the risks, a platform like the Chrome Web Store makes it much easier for users to discover your product compared to building a standalone website and competing with SEO. The key is diversification. A great example is Grammarly; they built a huge business around a browser extension but also invested in a web presence and actively engage with web standards and Chrome's development to mitigate platform risk.
Can you tell us about the sales process on Acquire.com?
Denis: It was quite a funnel. I had about 20-25 initial expressions of interest, which led to 10-15 calls with potential buyers. From there, it narrowed down to about five serious parties. A couple of them faced issues with financing or proposed seller-financing terms that weren't favorable. Ultimately, I received three serious offers around the same time, which gave me the luxury of choosing the right partner.
What made you choose Third South Capital as the buyer?
Denis: I wanted to be transparent with all potential buyers. My goal was to find someone who wouldn't just slightly improve the project and resell it in a couple of months. There were buyers who were open about that being their strategy, and others who just wanted the user base without investing in new features.
The Third South team was different.
They were ready to work on the project, improve it, grow it, and listen to the users. That was exactly what I wanted for the future of Clipboard History. One of the other buyers actually offered me about 10% more, but their intentions for the project didn't align with what I had envisioned.
"One of the other buyers actually offered me about 10% more, but their intentions for the project didn't align with what I had envisioned."
Looking back, what advice would you give to other independent engineers looking to sell their projects?
Denis: Numbers, numbers, numbers. As an engineer, I love the code, but you need to have your numbers clear. Keep your bookkeeping updated. When I started the sale process, I had no idea about my exact monthly revenue, conversion rates, or the number of pro users. If you prepare this information in advance, on a monthly basis, it makes the process so much easier.
My second piece of advice is more technical: whenever you start a new project, create a new dedicated email account for it. Clipboard History was tied to my personal account for years, which made the transfer process complicated. Using a separate account makes it much easier to manage, give access to contractors, and eventually transfer ownership. The transfer for TrackerJam took me three weeks of evening work. It's an obvious-sounding tip, but not everyone does it.
How do you balance adding new features versus keeping a product simple and user-friendly?
Denis: That is a great question, and I don't have a perfect answer. There are two forces at play. The engineer in me loves to create new features and tackle new technical challenges. But the product person in me knows that sometimes less is more. I always think of a tool called Bulk Rename Utility. It's an infamous example of terrible UX, with hundreds of buttons and input fields. It’s powerful, but overwhelming.
It's important to avoid overloading users and increasing the learning curve. Sometimes it's even good to remove features that aren't being used much. You have to find a balance. If competitors are adding a feature that users love, you probably need to consider it. But it's crucial to know your audience. A technical audience might appreciate more complexity and freedom, while a less technical audience needs simplicity.
With Clipboard History, the feature showing the character count of a copied item confused so many users. To me, it was obvious, but I got so many questions about what the numbers meant. Finding that balance is a secret I think everyone is trying to figure out.
What do you think you did particularly well with your successful projects that you'll carry forward?
Denis: One thing is finding the right balance with code quality for a side project. As a senior engineer at a big tech company, I'm used to writing high-quality, well-tested, documented code. But for an MVP, you have to lower your expectations. It's hard to write "bad" code, but spending weeks refactoring something that already works just delays your launch. I've learned when to invest in refactoring and when to start simple and iterate later.
"It's hard to write 'bad' code, but spending weeks refactoring something that already works just delays your launch."
The other crucial thing is to be a user of your own product. I tried building something I wasn't the target audience for with TrackerJam, and it didn't work for me. Clipboard History was successful because I built it for myself first. I implemented features that I wanted to use. When you get feedback and a user suggests something that you would also love to have, that's the sweet spot.
Can you give us a sneak peek at what you're working on now?
Denis: I've started working on a new project called Eventicat. It's a tool for technical founders and developers. We all use logs and event tracking, but it can be overwhelming to see a live stream of every single event. What I often want is just a summary. For example, every Friday, I want to know how many users registered that week. I couldn't find a simple tool that does this. Big companies have complex infrastructure for this, but it's overkill for small startups. So, I'm building a service where you can send your events, and it provides you with a nice summary on a schedule you set—daily, weekly, or monthly. It’s a problem I have myself, so even if I'm the only user, it will be worth it.
Colin Burns (Third South Capital): Denis, as we continue to grow Clipboard History Pro, are there any outstanding items on your wish list for the product?
Denis: I think diversifying beyond just the Chrome Web Store is a good long-term strategy. Creating a web-based panel or integrating with desktop clients that don't have a browser presence could be interesting directions. It would take significant technical work, of course, but it helps mitigate platform risk.
Myles Marino (Third South Capital): Finally, do you have any questions for us?
Denis: Now that you guys are working on Third South full-time, what are your next big milestones for the company? Are you thinking of combining your projects into a single ecosystem?
Colin Burns (Third South Capital): Our philosophy is to not just buy things to buy them. We want businesses we can grow. For example, another one of our companies is EntryThingy, a platform for artists to apply to calls for entry from galleries. The platform is amazing, but the front-end and back-end are dated.
We're currently rebuilding it—a project we're calling 'Re-entry thingy'—to modernize the UI/UX and make the back-end more robust, which will allow us to deploy changes much faster. Our focus is on being the right owners for a business and having a clear plan for how we can add value. It's about growth and stewardship, not just cost-cutting.
Denis: That's great to hear. It confirms I made the right choice in selling Clipboard History to you. It's really nice to see you working on the projects with that philosophy. I hope we can partner on something again someday.
