Ravindu Gajanayaka

Posted on Mar 7

I Can't Code, But I Built 3 Open-Source Business Apps — Here's How

#ai #beginners #productivity #opensource

I Can't Code, But I Built 3 Open-Source Business Apps — Here's How

I don't know Python. I can't write JavaScript from scratch. I've never formally learned any programming language.

But in the last year, I've built and shipped three open-source business applications that are live, functional, and growing. One of them is a full multi-tenant ERP system with 65+ database tables, real-time WebSocket updates, and AI-powered features.

This is how I did it.

My Background

I'm not a developer. I'm a guy from Sri Lanka who understands business operations — how a retail shop runs, how an auto service center manages work orders, how accounting should flow. I've worked with business software my whole career and always thought: "I could build something better than this."

The problem was always the same: I had the ideas but not the coding skills.

Then AI changed everything.

The Approach: AI as My Development Partner

I use AI tools — primarily Claude — as my coding partner. But let me be clear about what that means:

I don't just say "build me an app" and wait.

Here's what I actually do:

I design the system. I decide the database schema, the user flows, the business logic. I know what needs to be built because I understand the domain deeply.
I architect the solution. I choose the tech stack, plan the modules, decide how things connect. Multi-tenant architecture with row-level security? That was my decision based on real business needs.
I direct every feature. I work feature by feature, reviewing every piece of code, testing it, and iterating. If something doesn't work the way a real business needs it to, I know immediately.
AI writes the code. I describe what I need, review what it produces, and guide it to fix issues. Think of it like being an architect who doesn't lay bricks but designs the entire building.
I debug through conversation. When things break — and they do — I describe the problem and work through solutions. Over time, I've developed an intuition for common issues even without reading the code line by line.

The key insight: domain knowledge is more valuable than syntax knowledge. A developer who doesn't understand accounting will build a terrible accounting system, no matter how clean their code is.

What I Built

1. Retail Smart ERP

A multi-tenant SaaS Point of Sale and ERP system.

Tech: Next.js 16, React 19, PostgreSQL, WebSocket, Tailwind CSS

This is the big one. A complete business management system that supports five different business types:

Retail shops
Restaurants (with kitchen display and floor plans)
Supermarkets
Auto service centers (with work orders and vehicle tracking)
Vehicle dealerships

Features that I'm particularly proud of:

Multi-tenant with subdomain routing — each business gets company.retailsmarterp.com
Row-level security — tenant data isolation at the database level, not just application level
Real-time updates — WebSocket-powered, so every terminal sees changes instantly
AI-powered insights — smart warnings and anomaly detection
65+ database tables with proper double-entry accounting

Live: retailsmarterp.com
GitHub: github.com/ravindu2012/retail-smart-erp

2. POS Prime

A modern Point of Sale replacement for ERPNext.

Tech: Vue 3, TypeScript, Python, Frappe Framework, Tailwind CSS

ERPNext is a popular open-source ERP, but its built-in POS is slow and clunky. I built POS Prime as a complete replacement that:

Works on touch screens and barcode scanners
Has a self-checkout kiosk mode
Supports customer pole displays
Handles split payments and returns
Zero modifications to ERPNext — installs cleanly, uninstalls cleanly

The "zero modifications" part was a deliberate design decision. Too many ERPNext apps break upgrades because they add custom fields everywhere. POS Prime works entirely with standard ERPNext doctypes.

GitHub: github.com/ravindu2012/pos-prime

3. QuickBooks Desktop Clone

A full-featured desktop accounting application.

Tech: .NET 8, WPF, C#, Clean Architecture

This one targets small businesses that need proper accounting software but can't afford QuickBooks. Features include:

Double-entry accounting engine with 11 transaction posting types
65+ seeded Chart of Accounts
Customer and vendor management with aging reports
Invoice, bill, and payment processing
Banking and reconciliation
Full financial reporting (P&L, Balance Sheet, Trial Balance)

GitHub: github.com/ravindu2012/QuickBooksDesktop

What I've Learned

1. You don't need to know code to build software

You need to know what the software should do. The actual typing of code is becoming less important every day. Understanding user needs, business logic, data relationships, and system architecture — that's what matters.

2. AI is a tool, not a replacement for thinking

AI can write code, but it can't decide what to build. It can't tell you that auto service centers need to track core returns separately from regular parts. It can't tell you that restaurant POS needs a different flow than retail POS. Domain expertise is irreplaceable.

3. Start with what you know

All three of my projects come from domains I understand deeply. I didn't try to build a social media app or a game. I built business tools because that's where my knowledge lives.

4. Ship early, iterate often

My first version of Retail Smart ERP was embarrassingly basic. But it worked. Each week I added features, fixed issues, and improved the experience. Shipping beats perfection.

5. Open source amplifies everything

Making my projects open source was the best decision I made. It forced me to write better documentation, think about contributor experience, and build things that work for more than just me.

The Uncomfortable Truth

Some developers might read this and think it's "cheating" or "not real development." I understand that reaction.

But consider this: the end user doesn't care if a human typed every semicolon or if AI helped. They care that the POS system processes their sales correctly, that the accounting balances, and that their business data is secure.

I'm not claiming to be a senior developer. I'm a product builder who uses the best tools available. Five years ago, that might have meant hiring a team. Today, it means partnering with AI.

The barrier to building software has dropped dramatically. If you have deep knowledge in any field — healthcare, education, logistics, finance, anything — you can now turn that knowledge into real software.

Want to Contribute?

All three projects are open source and actively looking for contributors:

Retail Smart ERP — Next.js, React, PostgreSQL
POS Prime — Vue 3, Python, ERPNext
QuickBooks Desktop Clone — .NET 8, WPF, C#

Each repo has good first issue labels, contributing guides, and active discussions. Whether you're a seasoned developer or someone like me who's learning as they go — you're welcome.

If this project helps you or your business, consider supporting development: