The weekend that changed everything

Most successful products start with someone solving their own annoying problem.

David Bressler was on paternity leave in 2022, still grinding through Excel formulas for clients. He got tired of it and built a simple tool: describe what you need in plain English, get the formula instantly.

He called it Formula Bot and shared it online. It went viral almost immediately, and his OpenAI bill spiked into the thousands of dollars in the first week, before he had any pricing model in place.

He's since grown it into a bootstrapped, solo-founder business generating well into six figures annually, with no outside funding.

This breakdown looks at his tech stack, real costs, and how you could replicate a similar setup with different tools depending on your needs.

The real tech stack: Frontend and backend logic in Bubble.io · AI engine via the OpenAI API · Payments through Stripe · Monthly infrastructure cost roughly $2,500–$3,500

Why Bubble works here

Bubble is a strong fit for Formula Bot because the logic is straightforward: users upload data, ask questions, get results. No real-time collaboration. No thousands of concurrent users at once on a single session. No complex integrations. Bubble handles this comfortably at $29–65/month.

The OpenAI API is the larger recurring cost at this scale, running roughly $2,000–3,000/month, with Stripe taking its processing cut and email/hosting adding a few hundred more. That leaves healthy margins for a business run by one person.

But Bubble has limits. If you needed real-time collaborative editing, thousands of concurrent users, or integrations with 20+ systems, Bubble would start to strain. Most founders hit this wall and move to something more flexible.

How to replicate this with n8n instead

Maybe your problem is different and you need complex backend orchestration, asynchronous processing, or integration flexibility. That's where n8n comes in—think of it as a visual programming language for backends. You string together nodes like building blocks: API call → transform data → check condition → send to database → trigger email → log result.

The architecture would look like this:

The user experience stays identical. The backend is completely different, and considerably more flexible.

Why this matters: you own the entire backend, can add integrations without waiting on a platform's permission, build more complex logic, scale to thousands of concurrent users, and version control your workflows. A Bubble-plus-n8n approach costs somewhat more per month than Bubble alone, but it scales toward six-figure monthly revenue without breaking, where a Bubble-only stack would eventually struggle.

The honest truth

David solved a specific problem for a massive audience: Excel formulas. Nearly everyone uses Excel, and millions of people waste hours on syntax. His total addressable market is enormous.

If your problem is narrower, your ceiling is lower. That's math, not pessimism. What you can take from David's approach:

  1. Solve your own problem. He was genuinely frustrated, and that motivation matters.
  2. Launch fast. A weekend MVP beats a polished product that never ships.
  3. Choose the right tools. Bubble was the right fit for this specific problem.
  4. Stay capital efficient. Zero funding means every dollar counts more.
  5. Know when to go all-in. Revenue overtaking your salary is the clearest signal there is.

Which stack fits your situation?

Use Bubble + OpenAI if: your logic is straightforward, speed matters more than flexibility, and complexity is low.

Use Bubble + n8n if: you need flexible orchestration, multiple integrations, and you're thinking beyond an MVP.

Use pure n8n if: you're building an automation or integration business for other businesses and need white-label flexibility.

The real lesson

David built a serious annual business by seeing a problem, solving it in a weekend, and shipping it—no funding, no team, no overthinking.

The tools are more accessible than ever, and the barrier to entry keeps dropping. What separates the people who succeed is simple: ship first, optimize later, keep going when it's boring. The market doesn't care about your pedigree. It cares whether you solve a real problem better than anyone else.