How a Solo SaaS Founder Built a Business by Teaching First

**Fexingo** (0:01)
If these conversations are useful for what you're building or running, then today's angle might feel like a shortcut you wish you'd heard earlier. We're talking about a strategy I'm calling Teach to Build, where a solo founder creates educational content, even a full online course, before they write a single line of product code.

**Luna** (0:21)
So instead of building first and then trying to explain what you made, you explain first and then build what people actually ask for. That sounds backwards, but I've seen it work.

**Fexingo** (0:31)
Exactly. The specific case I want to dig into is a founder named Raj. He's a backend developer who spent years doing API integrations at a mid-sized fintech company. He noticed the same pain over and over.
Every new integration meant reading awful documentation, debugging edge cases, and rewriting boilerplate.

**Luna** (0:53)
The universal developer grown. I've heard that from a dozen founders.

**Fexingo** (0:58)
Right. So in early 2024, Raj decided he wanted to build a tool that automated the grunt work of API integration testing. But he didn't open an IDE.
Instead, he started a newsletter called API Hacks. Just weekly tips on handling authentication flows, rate-limiting webhook reliability, nothing so easy.

**Luna** (1:20)
How long did he do that before he even thought about a product?

**Fexingo** (1:24)
About four months.
He grew the newsletter to 1,800 subscribers just through Twitter threads and a few guest posts on dev blogs. Then he ran a survey, asked readers what their single biggest integration headache was. The top answer was testing webhooks in staging. That became his product thesis.

**Luna** (1:45)
So, he already had a warm audience that told him exactly what to build. That's way better than guessing.

**Fexingo** (1:52)
But he didn't stop there.
Before writing any code, he created a $49 video course called Webhook Testing Masterclass 7 Modules, Maybe 4 Hours of Content. He sold it to his newsletter list. 127 people bought it in the first two weeks. That's about $6,200 in revenue before he'd built anything beyond the landing page and some screen recordings.

**Luna** (2:17)
And that revenue is also a signal. If people pay $49 for a course on the problem, they'll probably pay $29 a month for a tool that solves it automatically.

**Fexingo** (2:28)
That's exactly the logic. Raj used the course as a validation funnel. He asked every buyer a follow-up question.
If I built a tool that did this in one click, would you use it?
86% said yes.
Then he asked about pricing. The median willingness to pay was $35 per month. So he had a price point, a feature list, and a pre-built audience of potential beta testers.

**Luna** (2:55)
What did he actually build?

**Fexingo** (2:57)
A SaaS tool called Staging Test. It lets developers simulate webhook events, inspect payloads, and replay failures, all without writing mock servers. He launched a closed beta to the course buyers in June 2024
41 people signed up for the $35 monthly plan on day one. That's recurring revenue before any public launch.

**Luna** (3:21)
And the course kept selling.
So he had two revenue streams feeding each other. The course brought in new people who eventually converted to the SaaS.

**Fexingo** (3:31)
Exactly. By the end of 2025, Raj had about 340 SaaS subscribers and total annual recurring revenue around $140,000. The course had sold about 800 copies total, bringing in another $39,000.
He was still a solo founder, no outside funding, and he worked on it evenings and weekends for the first nine months.

**Luna** (3:55)
I know that teach to build model is a new, people have been doing content led startups for a while. But what I like about Raj's story is the specificity. He didn't teach general how to be a developer.
He taught one narrow pain point, and that became his product SpeechHead.

**Fexingo** (4:12)
That's the key. The teaching has to be tightly coupled to the problem you're solving. If you teach a broad topic, your audience is too diffuse.
Raj's course was literally about the thing his tool would do. The course was the sales demo, the FAQ, and the user manual all rolled into one.

**Luna** (4:31)
Were there any downsides? I mean, creating a four-hour course takes time. That's time not spent building the product.

**Fexingo** (4:39)
Raj told me it took about 60 hours to produce the course. That's significant. But he also said that the course forced him to think through every edge case and work flow, which made the actual development faster. He had a clearer spec than he would have if he just started coding.

**Luna** (4:56)
So it's an investment that pays double. You get revenue and clarity.

**Fexingo** (5:01)