efficalc truss design

I've spent the past few years trying to build profitable side projects. My first two attempts sounded like such good ideas.

Both flopped without making a dime.

The third time, I finally learned from what I’d been doing wrong.

Here's what changed, and how a forgotten free tool became my first real revenue.

The projects I got wrong

Project #1: The revolutionary engineering workflow tool

I spent months building something technical and powerful, convinced it would change how structural engineers work. The tool was sophisticated, the code was clean, and I was certain the industry needed it.

The problem: I was trying to invent a new market, then teach people why they should care about what I'd built.

Total users: 2 (me and one guy from a Slack channel)

Lesson #1: Selling into existing markets where customers are actively searching for your product makes life much easier as a solo developer. My strength is in product building, not as much in selling.

Project #2: An AI learning app during the hype

I built what I thought was a useful wrapper around ChatGPT. The idea seemed solid at the time, and the AI hype was everywhere.

The problem: I had no distribution plan and was building what seemed cool to me rather than what people were actively looking for.

Revenue: $0

Lesson #2: Distribution is hard to manufacture. Every business is vying for customer attention. If no one sees your product, no one will buy your product.

What was sitting in front of me the whole time

While I was failing at those "innovative" ideas, I had a free truss analysis tool sitting on GitHub Pages. I'd built it three years earlier while learning React, then moved on to those "bigger opportunities" mentioned above.

But it kept growing quietly in the background:

March 2023: Added a simple email gate after users analyzed 3 trusses  

February 2025: Had collected 19,000 emails  

Emails sent to that list: Zero

After watching my other projects fail, the contrast became impossible to ignore:

- Failed projects: I built what I thought was cool → No one searched for it → No users

- Free truss tool: It solved a problem people were actively searching for → Organic growth → Real users

The thing I'd nearly forgotten about had more real traction than everything else I'd built combined.

The mental shift: Instead of trying to invent the next big thing, I should build what these 19,000 people were already asking for.

Applying what I'd learned: building something people wanted

This time, instead of inventing features I thought were cool, I went through years of user emails to see what people had actually been asking for.

What I built (February - October 2025):

- User accounts and Stripe integration

- Multiple load cases and member design (the most requested features)

- Improved editor and better performance

- Nothing revolutionary. Just the things people needed to get their work done.

Launch day (October 2025):  

I released a beta at half price: $10/month, $80/year, or $180 lifetime.

By the end of the first month, without any marketing or outreach, I had a handful of monthly subscribers and someone had purchased a lifetime license.

What felt different: This time I wasn't trying to convince anyone they needed something new. I had distribution through organic search traffic, and I was solving a problem people already knew they had.

They were already showing up - I just needed to give them a reason to pay.

Three months in: what worked differently this time

Month 1: $186 MRR  

Month 2: $340 MRR (I raised prices to $20/month in December)  

Month 3: $500 MRR

Total customers: 81 paid, 33 canceled

The numbers still felt small compared to the success stories you read about, but this was the first time strangers had actually paid me for something I built. That meant something.

Why this worked when the others didn't:

1. I had distribution before I started building

I wasn't trying to invent traffic or convince people to search for something new. People were already finding the free version through Google. I just needed to give them a reason to upgrade.

2. I built for existing, expressed demand

Users had literally emailed me asking for these specific features. There was no convincing required, no market education needed. They already knew what they wanted.

3. The customers surprised me (in a good way)

Not just engineering firms showed up. I also got DIY homeowners building additions, small contractors who couldn't justify $5,000/year for enterprise software, and solo engineers working on side projects.

They didn't want innovation or fancy features. They wanted something trustworthy and affordable for their specific project. The detailed calculation reports that showed exactly how results were calculated mattered more than any advanced feature I could have dreamed up.

4. I found problems worth solving

750 people created accounts but stopped at the paywall. That tells me my pricing clarity needs work. But at least people were showing up and interested enough to create accounts - that rarely happened with my previous projects.

What I'm still learning

The 32,000 email list I've never contacted

Those 19,000 emails have grown to over 32,000 now. I still haven't sent a single campaign to any of them.

Part of the hesitation is knowing that many are high school students - the free tool got linked by a popular STEM learning site. I don't want to spam kids about paid software. But there are also plenty of real engineers and contractors in there who might genuinely benefit from knowing about the pro version.

I need to figure out segmentation and actually use this asset I've been sitting on. It's on my list for the next few weeks.

The enterprise opportunity

Two weeks ago, I got an email from a truss manufacturing company asking if my software could replace their current design solution. That's a use case I hadn't really considered - companies that design trusses all day, every day.

At $500 MRR with 41% monthly churn, I know I'll hit a ceiling eventually if I want this to become full-time income. Maybe enterprise is the path to higher revenue and lower churn. Maybe it's something else I haven't thought of yet.